The pendulums measure the force of gravity in two ways.
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Today, their data come from two different instruments with pendulums.
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Speaking of pendulums, what do you think happens on Nov.
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When the ground moves, it sets the pendulums in motion as well.
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If we think history, say, pendulums and things reacting to different things.
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Keep an eye out for the next time the pendulums are restocked, too.
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All of these pendulums have swung more quickly than I thought they were going to swing.
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Within its sealed, insulated protective casting are three tiny pendulums, one for each axis of motion.
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To decrease noise from thermal changes, the delicate pendulums that detect vibration are within a vacuum chamber.
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Huygens noticed that the pendulums swung exactly in unison, always lurching toward each other and then away.
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Everyone's jaws are swinging like pendulums, so I decide to eat a cereal bar to fit in.
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It's also worthwhile to recognize that not all technology-driven pendulums of change always point toward digital.
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Instead of using the pendulums at Washington, small-force hunters could use spheres of silica levitated by lasers.
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For those new to divination practices, pendulums consist of a crystal, stone, or metal pendant on a long chain.
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As a child I was taught to fish, hunt, read the stars, dowse for water, and use pendulums for guidance.
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And this is also easiest for the wall; it no longer moves at all, because the pendulums are giving it equal and opposite kicks.
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In the new study, scientists performed two independent calculations of G using a pair of pendulums in a vacuum, one pendulum setup for each test.
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Once workers finish their task of assembling the gears, dials, levers, and pendulums that will make the clock run, it will only tick forward once a year.
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GrimaultWhen the seismometer originally underwent this battery of tests, engineers spotted an infinitesimally slow leak in the vacuum sphere that provides thermal shielding for its sensitive pendulums.
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Right now much of the discussion about jobs, automation and AI swings between two pendulums, explained Kristin Sharp, executive director of the Shift Commission at New America.
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But unlike the single, standing timepiece, it takes the form of 21 large-scale pendulums which immerse the audience in a fog of trailing light and echoing audio.
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"Pendulums have swung too far in the direction indicating doubt and pessimism with the changes that Facebook plans for its news feed," he wrote in a special note to CNBC.
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In the final piece of the course, it directed teachers to build pendulums with washers and string for an exercise where students would attempt to move the pendulum with their subconscious mind.
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Dowsing can be traced back to ancient China, Egypt, and Rome, where it's believed people used pendulums to ask divine entities questions like where they should plant crops or where spirits come from.
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In "Nowhere and Everywhere at the Same Time, No. 3" (2015), Mr. Forsythe has created a maze of 80 hanging pendulums — giving the spectator the playful (and humbling) task of navigating through them.
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For the pendulums, the most stable behavior is to move in opposite directions, so that each pushes the other in the direction it's already going, the way you push a child on a swing.
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The three worlds of Hunrath, Mofang, and Villein take center stage here, presenting us vividly colored ruins of Midwestern farmhouses, floating boulders overshadowed by two uncomfortably close moons, and strange, spiky pendulums loitering in metal corridors.
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Photos courtesy of United Visual Artists Each of the pendulums is a counterweighted two-axis robot arm containing a speaker and spotlight, which together form a system that allows for the synchronous and asynchronous movement throughout.
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As Emily Lakdawalla wrote in an article for The Planetary Society, the three VBBs were successfully re-centered and they appear to be working:The VBBs are pendulums mounted on pivots that are as nearly frictionless as possible.
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Then there was a section concerned with mindfulness, which centered on boilerplate audio you might expect from a meditation app, as well as instructions for a bizarre exercise that involved having students try to move pendulums with their minds.
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On its outbound journey it had not just been filled with sumptuous brocades and fussy mirrors, imposing pendulums, honeyed liqueurs and, quite possibly, portraits of the Sun King himself as tribute to the Kangxi emperor, fourth in the Qing dynasty.
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RICHMOND — A race that would tip control of Virginia's House of Delegates, whose constant and nearly comic pendulums between candidates has attracted national attention, took one more twist on Tuesday when a drawing to break a tie was unexpectedly postponed.
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Over the course of the 03th and 19th centuries, mathematicians became interested in studying periods generally—not just as they related to pendulums or planets, but as a class of numbers generated by integrating polynomial functions like x2 + 2x – 24 and 20x21 – 22x23 – 26x + 43.
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Napa wineries in particular go the extra mile when it comes to making caves desirable destinations for guided walks and tastings: Dotto modeled one of its wine caves after a Venetian palace; Stag&aposs Leap Wine Cellars is home to one of only 50 Foucault pendulums in the world; and Jarvis Estate&aposs cave features an underground waterfall.
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Later it was found that zinc is subject to creep. For these reasons mercury pendulums were used in the highest precision clocks, but gridirons were used in quality regulator clocks. Gridiron pendulums became so associated with good quality that, to this day, many ordinary clock pendulums have decorative 'fake' gridirons that don't actually have any temperature compensation function.
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Pendulums are also seen at many gatherings in eastern Mexico where they mark the turning of the tides on the day which the tides are at their highest point. See also pendulums for divination and dowsing.
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The difference between clock pendulums and gravimeter pendulums is that to measure gravity, the pendulum's length as well as its period has to be measured. The period of freeswinging pendulums could be found to great precision by comparing their swing with a precision clock that had been adjusted to keep correct time by the passage of stars overhead. In the early measurements, a weight on a cord was suspended in front of the clock pendulum, and its length adjusted until the two pendulums swung in exact synchronism. Then the length of the cord was measured.
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A schematic diagram of the Barton's pendulums experiment First demonstrated by Prof Edwin Henry Barton FRS FRSE (1858-1925), Professor of Physics at University College, Nottingham, who had a particular interest in the movement and behavior of spherical bodies, the Barton's pendulums experiment demonstrates the physical phenomenon of resonance and the response of pendulums to vibration at, below and above their resonant frequencies. In its simplest construction, approximately 10 different pendulums are hung from one common string. This system vibrates at the resonance frequency of a driver pendulum, causing the target pendulum to swing with the maximum amplitude. The other pendulums to the side do not move as well, thus demonstrating how torquing a pendulum at its resonance frequency is most efficient.
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For precise measurements, the optics must be isolated from ground motion and other influences from the environment. For this reason, all ground-based interferometric gravitational wave detectors suspend their mirrors as multi-stage pendulums. For frequencies above the pendulum resonance frequency, pendulums provide a good isolation against vibrations. All the main optics of GEO600 are suspended as triple pendulums, to isolate the mirrors from vibrations in the horizontal plane.
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One pendulum moves the pen back and forth along one axis, and the other pendulum moves the drawing surface back and forth along a perpendicular axis. By varying the frequency and phase of the pendulums relative to one another, different patterns are created. Even a simple harmonograph as described can create ellipses, spirals, figure eights and other Lissajous figures. More complex harmonographs incorporate three or more pendulums or linked pendulums together (for example, hanging one pendulum off another), or involve rotary motion, in which one or more pendulums is mounted on gimbals to allow movement in any direction.
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The equations of motion of inverted pendulums are dependent on what constraints are placed on the motion of the pendulum. Inverted pendulums can be created in various configurations resulting in a number of Equations of Motion describing the behavior of the pendulum.
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By making the rods of the correct lengths, the greater expansion of the zinc cancels out the expansion of the steel rods which have a greater combined length, and the pendulum stays the same length with temperature. Zinc-steel gridiron pendulums are made with 5 rods, but the thermal expansion of brass is closer to steel, so brass-steel gridirons usually require 9 rods. Gridiron pendulums adjust to temperature changes faster than mercury pendulums, but scientists found that friction of the rods sliding in their holes in the frame caused gridiron pendulums to adjust in a series of tiny jumps. In high precision clocks this caused the clock's rate to change suddenly with each jump.
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A study performed by Dr. Olmstead et al., described in detail elsewhere, demonstrates more concretely the influence that the semantics of action language can have on movement coordination. Briefly, this study investigated the effects of action language on the coordination of rhythmic bimanual hand movements. Subjects were instructed to move two pendulums, one with each hand, either in-phase (pendulums are at the same point in their cycle, phase difference of roughly 0 degrees) or anti-phase (pendulums are at the opposite point in their cycle, phase difference of roughly 180 degrees).
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Reversible pendulums remained the standard method used for absolute gravity measurements until they were superseded by free-fall gravimeters in the 1950s.
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Several variants of the double pendulum may be considered; the two limbs may be of equal or unequal lengths and masses, they may be simple pendulums or compound pendulums (also called complex pendulums) and the motion may be in three dimensions or restricted to the vertical plane. In the following analysis, the limbs are taken to be identical compound pendulums of length and mass , and the motion is restricted to two dimensions. Double compound pendulum Motion of the double compound pendulum (from numerical integration of the equations of motion) Trajectories of a double pendulum In a compound pendulum, the mass is distributed along its length. If the mass is evenly distributed, then the center of mass of each limb is at its midpoint, and the limb has a moment of inertia of about that point.
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Huygens coined the term centrifugal force in his 1659 De Vi Centrifiga and wrote of it in his 1673 Horologium Oscillatorium on pendulums.
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If the two pendulums are identical then one normal mode consists of both pendulums swinging in the same direction with a constant distance between them, while the other consists of the pendulums swinging in opposite (mirror image) directions. These normal modes have (slightly) different frequencies because the second involves the (weak) spring while the first does not. The initial state of the two-pendulum system is a combination of both normal modes. Over time, these normal modes drift out of phase, and this is seen as a transfer of motion from the first pendulum to the second.
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The Sackville complex was built in 1991, using the latest technology at the time. The lower foyer features one of the few Foucault's pendulums in the United Kingdom. As is common for Foucault pendulums that remain in use, it is now pushed by an electro-magnet. The Manchester Conference Centre's 117 bedroom hotel was rebranded in 2014 to The Pendulum Hotel.
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The most common pendulum length in quality clocks, which is always used in grandfather clocks, is the seconds pendulum, about long. In mantel clocks, half-second pendulums, long, or shorter, are used. Only a few large tower clocks use longer pendulums, the 1.5 second pendulum, long, or occasionally the two-second pendulum, Glasgow 1885, p.282 which is used in Big Ben.
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By his study of the oscillation period of compound pendulums Huygens made pivotal contributions to the development of the concept of moment of inertia.
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The Riddler Revenge is a Zamperla Giant Discovery frisbee ride that pendulums riders at Six Flags Over Texas. It opened on May 28, 2016.
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Some investigators have replaced the ankle inverted pendulum analogy with a model of double linked pendulums involving both hip and ankle sway. Neither model is accepted as more than an approximation. Analysis of postural sway shows much more variation than is seen in a physical pendulum or even a pair of coupled pendulums. Furthermore, quiet standing involves activity in all joints, not just the ankles or hips.
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View of the caves showing the two pendulums The Grotta Gigante horizontal pendulums are a pair of tiltmeters used for monitoring Earth movements, mounted in the Grotta Gigante in Italy. The horizontal pendulums, installed by the geodesist Antonio Marussi in 1959, are sensitive to deviations of the vertical, to rotations and shearing of the cave. The pendulum beam is suspended horizontally by two steel wires, an upper one fixed to the roof of the cave, the lower one fixed to the floor. The pendulum beam rotates in the horizontal plane around a virtual near-to-vertical axis that passes through the upper and lower mounting points.
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Experiments by Shortt showed that at 30 mm Hg the energy consumed by the flexing of the suspension spring just equalled the energy consumed by deflecting the residual air molecules and therefore a higher vacuum was not required. Both pendulums were seconds pendulums, about 1 meter (39 in) long, with a period of 2 seconds; each swing of the primary took exactly one second, with the secondary's natural rate very slightly longer. The pendulums received a push from the mechanism once every 30 seconds to keep them swinging. The secondary clock had two clock dials on it, showing the time kept by each pendulum, to verify that they were synchronized.
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This is a list of Foucault pendulums in the world: Artistic rendition (highly exaggerated) of a Foucault pendulum showing that the Earth is not stationary, but rotates.
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Almost a variety of tassel tie-back, the pendulum tie-back consists of one or two large handing decorative pendulums attached to ropes which loop around the curtain.
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The physicist and astronomer Galilee would have had observed a swinging chandelier in the Pise cathedral that gave him the beginnings of its theory on pendulums oscillations isochronism.
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Pendulum and anchor escapement from a grandfather clock Animation of anchor escapement, one of the most widely used escapements in pendulum clock. For 300 years, from its discovery around 1582 until development of the quartz clock in the 1930s, the pendulum was the world's standard for accurate timekeeping.Milham 1945, p.334 In addition to clock pendulums, freeswinging seconds pendulums were widely used as precision timers in scientific experiments in the 17th and 18th centuries.
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Experiments involving pendulums continued to be performed in the first half of the 19th century. By the second half of the century, these were outperformed by repetitions of the Cavendish experiment, and the modern value of G (and hence, of the Earth mass) is still derived from high-precision repetitions of the Cavendish experiment. In 1821, Francesco Carlini determined a density value of ρ = through measurements made with pendulums in the Milan area.
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Most of the gross inaccuracy of the early verge and foliot clocks was not due to the escapement itself, but to the foliot oscillator. The first use of pendulums in clocks around 1656 suddenly increased the accuracy of the verge clock from hours a day to minutes a day. Most clocks were rebuilt with their foliots replaced by pendulums,Milham 1945, p.144 to the extent that it is difficult to find original verge and foliot clocks intact today.
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The first pendulum clock was invented in 1656 by Dutch scientist and inventor Christiaan Huygens, and patented the following year. Huygens contracted the construction of his clock designs to clockmaker Salomon Coster, who actually built the clock. Huygens was inspired by investigations of pendulums by Galileo Galilei beginning around 1602. Galileo discovered the key property that makes pendulums useful timekeepers: isochronism, which means that the period of swing of a pendulum is approximately the same for different sized swings.
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As in the older Keio Plaza Hotel, some fire escape exits are exposed outside the building to prevent smoke from accumulating in the case of fire. In 2013, Mitsui Fudosan and Kajima Corporation began installing six massive pendulums on the roof of the building to counter long-period earthquake ground motion. The pendulums will reduce magnitude of building motion by half or more during a major earthquake, such as the Great East Japan earthquake of 2011.
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A physical system can have as many resonant frequencies as it has degrees of freedom; each degree of freedom can vibrate as a harmonic oscillator. Systems with one degree of freedom, such as a mass on a spring, pendulums, balance wheels, and LC tuned circuits have one resonant frequency. Systems with two degrees of freedom, such as coupled pendulums and resonant transformers can have two resonant frequencies. A crystal lattice composed of N atoms bound together can have N resonant frequencies.
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Around 99% of the energy loss in a freeswinging pendulum is due to air friction, so mounting a pendulum in a vacuum tank can increase the Q, and thus the accuracy, by a factor of 100.Matthys, 2004, p.81 The Q of pendulums ranges from several thousand in an ordinary clock to several hundred thousand for precision regulator pendulums swinging in vacuum. A quality home pendulum clock might have a Q of 10,000 and an accuracy of 10 seconds per month.
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That is, their pendulums were beating in unison but in the opposite direction; 180° out of phase. Regardless of how the two clocks were started, he found that they would eventually return to this state, thus making the first recorded observation of a coupled oscillator. The cause of this behavior was that the two pendulums were affecting each other through slight motions of the supporting mantlepiece. This process is called entrainment or mode locking in physics and is observed in other coupled oscillators.
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Lateral view of a longcase clock movement without striking mechanism, mid-1800s. The advent of the longcase clock is due to the invention of the anchor escapement mechanism by Robert Hooke around 1658. Prior to the adoption of the anchor mechanism, pendulum clock movements used an older verge escapement mechanism, which required very wide pendulum swings of about 80–100°. Long pendulums with such wide swings could not be fitted within a case, so most freestanding clocks had short pendulums.
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Between 1886 and 1895 Rebeur- Paschwitz developed three models of pendulums. He collaborated with three different manufacturers: the Fecker pendulum in 1886, the Repsold pendulum in 1888, and the Stückrath two-component model in 1894. Seismogram records in Potsdam and Wilhelmshaven, from von Rebeur-Paschwitz Rebeur-Paschwitz installed one of his pendulum in Potsdam and the second one in Wilhelmshaven close to the North Sea. The pendulums designed to measure the horizontal motion of the ground due to supposed lunar tides.
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Skeletons are capable of scaling walls. Other dangers include lava, fireballs, giant sharp pendulums, and various other booby traps. Trine uses Nvidia's PhysX physics engine to provide objects and characters with full physics interaction.
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Galileo discovered the crucial property that makes pendulums useful as timekeepers, called isochronism; the period of the pendulum is approximately independent of the amplitude or width of the swing. He also found that the period is independent of the mass of the bob, and proportional to the square root of the length of the pendulum. He first employed freeswinging pendulums in simple timing applications. His physician friend, Santorio Santorii, invented a device which measured a patient's pulse by the length of a pendulum; the pulsilogium.
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The NASA team will compare their results with a similar test by Edcon Inc., a gravitometer manufacturer in Denver, as well as observations at Foucault pendulums in Europe that lie in the path of the eclipse.
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Gravimeter with variant of Repsold pendulum The large increase in gravity measurement accuracy made possible by Kater's pendulum established gravimetry as a regular part of geodesy. To be useful, it was necessary to find the exact location (latitude and longitude) of the 'station' where a gravity measurement was taken, so pendulum measurements became part of surveying. Kater's pendulums were taken on the great historic geodetic surveys of much of the world that were being done during the 19th century. In particular, Kater's pendulums were used in the Great Trigonometric Survey of India.
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Acting as tutor, Gregory was also an examiner of his college and lectured occasionally in chemistry. Two of his papers explored the physics of pendulums (clockmakers) and were written with Mr. Archibald Smith.Philosophical Magazine Vol. XXXI Jan.-Jun.
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Pendulum type scales do not use springs. This design uses pendulums and operates as a balance and is unaffected by differences in gravity. An example of application of this design are scales made by the Toledo Scale Company.
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Its available space and the constant temperatures throughout the year have led to the placement of scientific instruments, including the two Grotta Gigante horizontal pendulums which hang down from about , and are the longest geodetic pendula in the world.
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Visitors each had a unique experience of the work according to their movement, and the movement of the pendulums. Momentum is one of the gallery’s most popular exhibitions to date with over 77,500 visitors, an average of 717 visitors per day.
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Rasmussen was alleged to have produced psychokinetic phenomena, such as moving pendulums in sealed glass cases.Anderson, Rodger. (2006). Psychics, Sensitives and Somnambules: A Biographical Dictionary with Bibliographies. McFarland. p. 118. She was endorsed as genuine by the psychical researcher Harry Price.
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Although a pendulum can theoretically be any shape, any rigid object swinging on a pivot, clock pendulums are usually made of a weight or bob attached to the bottom end of a rod, with the top attached to a pivot so it can swing. The advantage of this construction is that it positions the centre of mass close to the physical end of the pendulum, farthest from the pivot. This maximizes the moment of inertia, and minimises the length of pendulum required for a given period. Shorter pendulums allow the clock case to be made smaller, and also minimize the pendulum's air resistance.
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The anchor also allowed the use of a heavier pendulum bob for a given drive force, making the pendulum more independent of the escapement (higher Q), and thus more accurate. These long pendulums required long narrow clock cases. Around 1680 British clockmaker William Clement began selling the first commercial clocks to use the anchor escapement, tall freestanding clocks with 1 meter (39 inch) seconds pendulums that came to be called longcase or 'grandfather' clocks. The anchor increased the accuracy of clocks so much that around 1680–1690 the use of the minute hand, formerly the exception in clocks, became the rule.
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In addition to increased accuracy, the anchor's narrow pendulum swing allowed the clock's case to accommodate longer, slower pendulums, which needed less power and caused less wear on the movement. The seconds pendulum (also called the Royal pendulum), 0.994 m (39.1 in) long, in which each swing takes one second, became widely used in quality clocks. The long narrow clocks built around these pendulums, first made by William Clement around 1680, became known as grandfather clocks. The increased accuracy resulting from these developments caused the minute hand, previously rare, to be added to clock faces beginning around 1690.
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Harmonograph A harmonograph A harmonograph is a mechanical apparatus that employs pendulums to create a geometric image. The drawings created typically are Lissajous curves or related drawings of greater complexity. The devices, which began to appear in the mid-19th century and peaked in popularity in the 1890s, cannot be conclusively attributed to a single person, although Hugh Blackburn, a professor of mathematics at the University of Glasgow, is commonly believed to be the official inventor. A simple, so-called "lateral" harmonograph uses two pendulums to control the movement of a pen relative to a drawing surface.
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In addition to increased accuracy, the anchor's narrow pendulum swing allowed the clock's case to accommodate longer, slower pendulums, which needed less power and caused less wear on the movement. The seconds pendulum (also called the Royal pendulum), 0.994 m (39.1 in) long, in which the time period is two seconds, became widely used in quality clocks. The long narrow clocks built around these pendulums, first made by William Clement around 1680, became known as grandfather clocks. The increased accuracy resulting from these developments caused the minute hand, previously rare, to be added to clock faces beginning around 1690.
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This he directly tested, twice, by using stars to mark time and recruiting a team of nine fellow Jesuits to count swings and maintain the amplitude of swing for 24 hours. The results were pendulums with periods within 1.85%, and then 0.69%, of the desired value; and Riccioli even sought to improve on the latter value. The seconds pendulum was then used as a standard for calibrating pendulums with different periods. Riccioli said that for measuring time a pendulum was not a perfectly reliable tool, but in comparison with other methods it was an exceedingly reliable tool.
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The Shortt clock consists of two separate units: the primary pendulum in a copper vacuum tank 26 cm diameter and 125 cm high attached to a wall, and a precision pendulum clock locked to it, standing a few feet away. To prevent any possibility of coupling between the pendulums, the two units were either installed far apart in different rooms, or the units were oriented so the planes of swing of the two pendulums were ninety degrees apart. The secondary clock was a modified version of a standard Synchronome precision regulator clock. The two components were linked by wires which carried electric pulses that operated electromagnets in the mechanisms to keep the two pendulums swinging in synchronism. The primary pendulum rod and its 14-pound weight were made of the alloy invar to reduce thermal expansion and contraction of the pendulum, which causes the pendulum's period to vary with changes in temperature.
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To accomplish this, Margolis Method focuses on theatrical notions like conflict, timing, and neutrality and employs concepts borrowed from physics, such as inertia, lines of force and density (as well as concrete manifestations of these principles, such as: pendulums, pulleys and elastics).
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This hall gives visitors the chance to experience physical phenomena and solve problems using interactive exhibits. Gyroscopes, levers, pendulums, the Venturi effect, gears.... these are just some examples of the experiments which give visitors the chance to have fun while they learn.
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This was the first demonstration of the Earth's rotation that didn't depend on celestial observations,Amir Aczel (2003) Leon Foucault: His life, times and achievements, in and a "pendulum mania" broke out, as Foucault pendulums were displayed in many cities and attracted large crowds.
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In 1895, Lippmann evolved a method of eliminating the personal equation in measurements of time, using photographic registration, and he studied the eradication of irregularities of pendulum clocks, devising a method of comparing the times of oscillation of two pendulums of nearly equal period.
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Location of Taipei 101's largest tuned mass damper Typically, the dampers are huge concrete blocks or steel bodies mounted in skyscrapers or other structures, and moved in opposition to the resonance frequency oscillations of the structure by means of springs, fluid or pendulums.
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The anchor was the second widely used escapement in Europe, replacing the primitive 400-year-old verge escapement in pendulum clocks. The pendulums in verge escapement clocks had very wide swings of 80° to 100°. In 1673, seventeen years after he invented the pendulum clock, Christiaan Huygens published his mathematical analysis of pendulums, Horologium Oscillatorium. In it he showed that the wide pendulum swings of verge clocks caused them to be inaccurate, because the period of oscillation of the pendulum was not isochronous but varied to a small degree due to circular error with changes in the amplitude of the pendulum's swing, which occurred with unavoidable changes in drive force.
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Pendulums are also used in scientific instruments such as accelerometers and seismometers. Historically they were used as gravimeters to measure the acceleration of gravity in geo- physical surveys, and even as a standard of length. The word "pendulum" is new Latin, from the Latin pendulus, meaning 'hanging'.
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The force exerted by Earth's gravity can be used to calculate its mass. Astronomers can also calculate Earth's mass by observing the motion of orbiting satellites. Earth's average density can be determined through gravimetric experiments, which have historically involved pendulums. The mass of Earth is about .
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By means of pendulums suspended on the dam wall the degree of flex can be measures. The movement of segments relative to one another is also under constant observation. The wall has several galleries for inspection purposes. Two bottom outlets have been installed at the base.
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The firm acquired a reputation for building particularly fine regulators. Up to the 1920s it still produced regulators with compensated pendulums and precision movements. The firm was later taken over by Junghans and the factory closed down in 1932, at which period the market for wall regulators had collapsed.
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Most medieval clocks had their foliots replaced by pendulums after 1657 when the pendulum was invented. In the 19th century this misled scholars into thinking the clock may have been made as early as 1348. In the 20th century the date of the clock was revised to about 1600.
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Spring-driven pendulum clock, designed by Huygens, built by instrument maker Salomon Coster (1657), and a copy of the Horologium Oscillatorium. Museum Boerhaave, Leiden In 1673 Huygens published Horologium Oscillatorium sive de motu pendulorum, his major work on pendulums and horology. It had been observed by Mersenne and others that pendulums are not quite isochronous: their period depends on their width of swing, with wide swings taking slightly longer than narrow swings.Marin Mersenne 1647 Reflectiones Physico-Mathematicae, Paris, Chapter 19, cited in Huygens analyzed this problem by finding the curve down which a mass will slide under the influence of gravity in the same amount of time, regardless of its starting point; the so-called tautochrone problem.
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Needham, Volume 3, 627-629 Released by a lever, a small ball would fall out of the urn-shaped device into one of eight metal toad's mouths below, at the eight points of the compass, signifying the direction the earthquake was located. Many sources claim that the 10th-century Egyptian astronomer Ibn Yunus used a pendulum for time measurement, but this was an error that originated in 1684 with the British historian Edward Bernard. During the Renaissance, large hand-pumped pendulums were used as sources of power for manual reciprocating machines such as saws, bellows, and pumps. Leonardo da Vinci made many drawings of the motion of pendulums, though without realizing its value for timekeeping.
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To accommodate the wide pendulum swings caused by the verge escapement, "wings" have been added on the sides Grandfather clock These early clocks, due to their verge escapements, had wide pendulum swings of 80–100°. In his 1673 analysis of pendulums, Horologium Oscillatorium, Huygens showed that wide swings made the pendulum inaccurate, causing its period, and thus the rate of the clock, to vary with unavoidable variations in the driving force provided by the movement. Clockmakers' realization that only pendulums with small swings of a few degrees are isochronous motivated the invention of the anchor escapement by Robert Hooke around 1658, which reduced the pendulum's swing to 4–6°. The anchor became the standard escapement used in pendulum clocks.
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He was best known for his work on temperature compensated pendulums and his use of the cylinder escapement. His quality workmanship led to an appointment as Clockmaker to George III. His son Edward (-1791), joined the business in 1760. Over their twelve-year partnership, their clocks were simply signed Ellicott, London.
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Riccioli is credited with being the first person to precisely measure the acceleration due to gravity of falling bodies.Koyré 1955 (p. 349); Graney 2012. Books 2 and 9 of the New Almagest Riccioli included a significant discussion of and extensive experimental reports on the motions of falling bodies and pendulums.
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It is Huygens' major work on pendulums and horology. As Domenico Bertoloni Meli (2006) notes, Horologium Oscillatorium was “a masterful combination of sophisticated mathematics and mechanics mixed with a range of practical applications culminating with a new clock aimed at resolving the vexing problem of longitude.”Meli, Domenico Bertoloni (2006).
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Under the pendulums, there are floor goals that are alliance- specific. On two of the corners, there are flags on PVC poles. In the other two corners, there are trapezoidal areas with plastic cube scoring objects. The field is also divided into two triangular halves, one red and one blue.
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Eventually all of the system's energy is transferred to the second pendulum and the first is at rest. The process then reverses. The energy oscillates between the two pendulums repeatedly until it is lost to friction. The behavior of this system can be understood by looking at its normal modes of oscillation.
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Invar pendulums were first used in 1898 in the Riefler regulator clockMilham 1945, p.331-332 which achieved accuracy of 15 milliseconds per day. Suspension springs of Elinvar were used to eliminate temperature variation of the spring's restoring force on the pendulum. Later fused quartz was used which had even lower CTE.
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The uppermost and the intermediate mass are hung from cantilever springs, which provide isolation against vertical movement. On the uppermost mass are six coil-magnet actuators that are used to actively dampen the pendulums. Furthermore, the whole suspension cage sits on piezo crystals. The crystals are used for an ‘active seismic isolation system’.
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This was solved with the invention of temperature compensated pendulums, the mercury pendulum in 1721 cited in and the gridiron pendulum in 1726, reducing errors in precision pendulum clocks to a few seconds per week. The accuracy of gravity measurements made with pendulums was limited by the difficulty of finding the location of their center of oscillation. Huygens had discovered in 1673 that a pendulum has the same period when hung from its center of oscillation as when hung from its pivot, and the distance between the two points was equal to the length of a simple gravity pendulum of the same period. In 1818 British Captain Henry Kater invented the reversible Kater's pendulum which used this principle, making possible very accurate measurements of gravity.
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Pendulums are affected by changes in gravitational acceleration, which varies by as much as 0.5% at different locations on Earth, so precision pendulum clocks have to be recalibrated after a move. Even moving a pendulum clock to the top of a tall building can cause it to lose measurable time from the reduction in gravity.
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Under the right conditions, chaos spontaneously evolves into a lockstep pattern. In the Kuramoto model, four conditions suffice to produce synchronization in a chaotic system. Examples include the coupled oscillation of Christiaan Huygens' pendulums, fireflies, neurons, the London Millennium Bridge resonance, and large arrays of Josephson junctions.Steven Strogatz, Sync: The Emerging Science of Spontaneous Order, Hyperion, 2003.
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Often, this term is used without considering the causes of a particular event. Example of a physical phenomenon is an observable phenomenon of the lunar orbit or the phenomenon of oscillations of a pendulum. A mechanical phenomenon is a physical phenomenon associated with the equilibrium or motion of objects. Some examples are Newton's cradle, engines, and double pendulums.
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Two pendulums with the same period coupled by suspending them from a common support string. The oscillation alternates between the two. Repetition of Huygens experiment showing synchronization of two clocks In 1665 Huygens made a curious observation about pendulum clocks. Two clocks had been placed on his mantlepiece, and he noted that they had acquired an opposing motion.
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Areas where the Pendulum does not shine are affected by permanent manifestations of the Dream. The Aran world is a separate existence, accessible only in places the Pendulums' light cannot reach (underground or deep underwater). It is fiercely primordial, rejecting inorganic matter and operating by rules entirely different from reality. The creatures inhabiting Aran are unpredictable and poorly understood.
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The bells consist of a metal stand with a crossbar, from which hang three bells. The outer two bells hang from conductive metal chains, while the central bell hangs from a nonconductive thread. In the spaces between these bells hang two metal clappers, small pendulums, on nonconductive threads. A short metal chain hangs from the central bell.
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He requested missionary work, but that request was turned down. Instead, he was assigned to teach at Parma. There he taught logic, physics, and metaphysics from 1629 to 1632, and engaged in some experiments with falling bodies and pendulums. In 1632 he became a member of a group charged with the formation of younger Jesuits, among whom Daniello Bartoli.
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In physics, two objects are said to be coupled when they are interacting with each other. In classical mechanics, coupling is a connection between two oscillating systems, such as pendulums connected by a spring. The connection affects the oscillatory pattern of both objects. In particle physics, two particles are coupled if they are connected by one of the four fundamental forces.
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In 1656 the Dutch scientist Christiaan Huygens built the first pendulum clock.although there are unsubstantiated references to prior pendulum clocks made by others: This was a great improvement over existing mechanical clocks; their best accuracy was improved from around 15 minutes deviation a day to around 15 seconds a day. Pendulums spread over Europe as existing clocks were retrofitted with them.Milham 1945, p.
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Mattheys, 2004, p. 13 Instead of hanging from a pivot, clock pendulums are usually supported by a short straight spring (d) of flexible metal ribbon. This avoids the friction and 'play' caused by a pivot, and the slight bending force of the spring merely adds to the pendulum's restoring force. The highest precision clocks have pivots of 'knife' blades resting on agate plates.
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See Bernan's History and Art of Warming and Ventilation, 1845, ii. 70 In 1787, age 74, a year before his death, he published An Attempt towards obtaining invariable Measures of Length, Capacity, and Weight, from the Mensuration of Time (London). Whitehurst wanted to study the shape of the earth by measuring differences in gravitation. For this, he studied heavy pendulums in different locations.
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Most commercial units are self-balancing in the direction of travel only (single axis) with lateral stability being provided by the rider; more complex fully self-balancing dual-axis devices also need to self-balance from side to side. The control mechanisms of both use control moment gyroscopes, reaction wheels and/or auxiliary pendulums and can be considered to be inverted pendulum.
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His reputation for quality tower clocks spread and he soon was receiving other orders for his Century tower clocks. Johnson desired to make a couple of clocks with sufficiently uniform pendulums that they would beat synchronously, however he could not accomplish this. He presented this problem to science professors at the University of Michigan. They pointed out to Johnson that it was impossible.
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Huygens claimed it achieved an accuracy of 10 seconds per day. The pendulum clock was invented in 1656 by Dutch scientist and inventor Christiaan Huygens, and patented the following year. Huygens contracted the construction of his clock designs to clockmaker Salomon Coster, who actually built the clock. Huygens was inspired by investigations of pendulums by Galileo Galilei beginning around 1602.
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Giovanni Ceva also studied applications of mechanics and statics to geometric systems. At one point, however, he incorrectly resolved that the periods of oscillation of two pendulums were in the same ratio as their lengths, but he later realized and corrected the error. Ceva also worked on hydraulics. In 1728, he published Opus hydrostaticum which discusses his work in hydraulics.
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Ernst von Rebeur-Paschwitz (9 August 1861, Frankfurt (Oder) – 1 October 1895, Merseburg) was a German astronomer, geophysicist and seismologist. He is best known for the first recording of teleseism with the use of his sensitive self- registering horizontal pendulums in 1889. He proposed to create an international network of seismological stations. His ideas led to the founding of the International Seismological Association.
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Peirce used swinging pendulums often of his own design. This practical involvement in physics played a major role in his Peirce's rejection scientific determinism. Lenzen's investigations led to the location of these report by Coast Survey archivist, Albert Whimpey in 1968. When Lenzen studied the papers he found that Peirce had first presented an overview of his methodology before presenting the data.
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The field for the competition is a square measuring 12 feet by 12 feet, which can be constructed by teams for practising prior to competitions.. USFIRST.org. Retrieved 2013-9-7. In the centre of the field there is a wooden "bridge" with a metal pipe that robots will hang on. On each side of the bridge, there are pendulums with crates.
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Part of the contents originally planned for the first book was divided out into a second book, which largely concerns motion through resisting mediums. Just as Newton examined consequences of different conceivable laws of attraction in Book 1, here he examines different conceivable laws of resistance; thus Section 1 discusses resistance in direct proportion to velocity, and Section 2 goes on to examine the implications of resistance in proportion to the square of velocity. Book 2 also discusses (in Section 5) hydrostatics and the properties of compressible fluids; Newton also derives Boyle's law. The effects of air resistance on pendulums are studied in Section 6, along with Newton's account of experiments that he carried out, to try to find out some characteristics of air resistance in reality by observing the motions of pendulums under different conditions.
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Rebeur-Paschwitz realized the necessity for international cooperation in the field of seismology, and in 1895 at the International Geographical Congress proposed to install a homogeneous global seismological station network equipped with horizontal pendulums. As a result, Englishman John Milne established network of stations with simply-to-use horizontal pendulums in the British colonies. In his last publication of the same year, Rebeur-Paschwitz also argued for establishing an internationally centralized bureau to collect global seismological observations. Georg C. K. Gerland presented Rebeur-Paschwitz’s ideas at the sixth International Geographic Conference in London in 1895, and organized the first International Conference of Seismology in Strasbourg in 1901. It was the start of international cooperation in seismology and led to the founding two years later of the International Seismological Association (since 1951 the International Association of Seismology and Physics of the Earth’s Interior (IASPEI)).
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The earthquake was strong at Pasto, Ipiales, Imuesa, Tuquerres and Sapuyas; it lasted about 40 minutes, but did not cause material damage. At Cali and Pereira, the population was frightened. At Bogotá, the pendulums stopped on the clocks at the seismic station. Many recurrent shocks were felt at the epicentral zone; the two strongest occurred on January 19 at 9:45 and on February 1.
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A double inverted pendulum is the combination of the inverted pendulum and the double pendulum. The double inverted pendulum is unstable, meaning that it will fall down unless it is controlled in some way. The two main methods of controlling a double inverted pendulum are moving the base, as with the inverted pendulum, or by applying a torque at the pivot point between the two pendulums.
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Shortt-Synchronome free pendulum clock, the most accurate pendulum clock ever made, at the NIST museum, Gaithersburg, MD, USA. It kept time with two synchronized pendulums. The master pendulum in the vacuum tank (left) swung free of virtually any disturbance, and controlled the slave pendulum in the clock case (right) which performed the impulsing and timekeeping tasks. Its accuracy was about a second per year.
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Its invention is important in the history of technology, because it made possible the development of all-mechanical clocks. This caused a shift from measuring time by continuous processes, such as the flow of liquid in water clocks, to repetitive, oscillatory processes, such as the swing of pendulums, which had the potential to be more accurate., p.31 Oscillating timekeepers are used in all modern timepieces.
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About 100 were produced between 1922 and 1956. Shortt clocks kept time with two pendulums, a primary pendulum swinging in a vacuum tank and a secondary pendulum in a separate clock, which was synchronized to the primary by an electric circuit and electromagnets. The secondary pendulum was attached to the timekeeping mechanisms of the clock, leaving the primary pendulum virtually free of external disturbances.
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Commands from the theodolite were transmitted via cables to the vehicle, to torquers in the ST-124 to orient the stable platform toward the correct azimuth. The gyros, accelerometers and pendulums contain almost frictionless nitrogen gas bearings. These required very precise machining and very small gaps between the bearing surfaces. Dimensions were held to tolerances of , and the gap filled by the nitrogen is about .
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Years later, in 1955 Chile installed the Aguirre Cerda Base a few hundred meters from the refuge. A volcanic eruption on December 4, 1967, devastated the Chilean base and the Argentine refuge. The name of the cove, which was also given to the refuge, recalls the magnetic observations made with pendulums in the place by the British expedition headed by Henry Foster in 1828.
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By moving the Game Boy Advance side to side, players tilt the world around Yoshi, causing enemies to roll around, swinging ships and pendulums, and bouncing items all over the place. An impassable wall will become a climbable slope, or a rolled-up carpet will become a long platform. Each environment requires players to master not only button presses but also tilt movements to progress.
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The first example of cranial kinesis was in the chondrichthyans, such as sharks. There is no attachment between the hyomandibular and the quadrate, and instead the hyoid arch suspends the two sets of jaws like pendulums. This allows sharks to swing their jaws outwards and forwards over the prey, allowing the synchronous meeting of the jaws and avoiding deflecting the prey when it comes close.
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Wundt arranged for the construction of suitable instruments and collected many pieces of equipment such as tachistoscopes, chronoscopes, pendulums, electrical devices, timers, and sensory mapping devices, and was known to assign an instrument to various graduate students with the task of developing uses for future research in experimentation.Wontorra: Frühe apparative Psychologie, 2009. Between 1885 and 1909, there were 15 assistants.Anneros Meischner-Metge: Wilhelm Wundt und seine Schüler.
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During the 1800s, conical pendulums were used as the timekeeping element in a few clockwork timing mechanisms where a smooth motion was required, as opposed to the unavoidably jerky motion provided by ordinary pendulums. Two examples were mechanisms to turn the lenses of lighthouses to sweep their beams across the sea, and the location drives of equatorial mount telescopes, to allow the telescope to follow a star smoothly across the sky as the Earth turns. One of the most important uses of the conical pendulum was in the flyball governor (centrifugal governor) invented by James Watt in 1788 which regulated the speed of steam engines during the Steam Age in the 1800s. The playground game tetherball uses a ball attached to a pole by a cord which functions as a conical pendulum, although the pendulum gets shorter as the cord wraps around the pole.
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In 2004, she released All of Our Names. The album included the singles "Almost", which made the top 20 on Canadian pop charts, and "Pendulums". Her fourth album, I'm a Mountain, was released in Canada on November 2005 and in the United States in February 2006. It was nominated for the 2006 Polaris Music Prize, a jury-selected $20,000 cash prize for the Canadian album of the year.
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A double pendulum consists of two pendulums attached end to end. In physics and mathematics, in the area of dynamical systems, a double pendulum is a pendulum with another pendulum attached to its end, and is a simple physical system that exhibits rich dynamic behavior with a strong sensitivity to initial conditions. The motion of a double pendulum is governed by a set of coupled ordinary differential equations and is chaotic.
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Pendulums are widely used in science education as an example of a harmonic oscillator, to teach dynamics and oscillatory motion. One use is to demonstrate the law of conservation of energy. A heavy object such as a bowling ball or wrecking ball is attached to a string. The weight is then moved to within a few inches of a volunteer's face, then released and allowed to swing and come back.
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He found upon experiment that the actual difference was only 59.892 inches owing to the real length of the pendulum, oscillating once a second, being 39.125 inches. He obtained rough data, from which the true lengths of pendulums, the spaces through which heavy bodies fall in a given time, and many other particulars relating to the force of gravitation and the true figure of the earth could be deduced.
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Wristwatches and smaller clocks do not use pendulums as the timing device. Instead, they use a balance spring: a fine spring connected to a metal balance wheel that oscillates (rotates back and forth). Most modern mechanical watches have a working frequency of 3–4 Hz, or 6–8 beats per second (21,600–28,800 beats per hour; bph). Faster or slower speeds are used in some watches (33,600bph, or 19,800bph).
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The film opens with a montage of scenes of elemental violence—crashing waves and falling trees alternate with images of trees speeding past as if viewed from a motorcar. The imagery gradually changes to more tranquil vistas of clouds, grass swaying in a breeze, and rippling water. The first interior shot shows a woman silhouetted against a window. There are several shots of a fireplace and of clocks and their pendulums.
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The mechanism of the astronomical clock occupies a large space within the tower behind the visible clock. It is almost tall and stretches through three storeys of the tower. In addition, lines connecting the mechanism with one of the tower clocks and the pendulums run from the top of the tower to its basement. The complex mechanism still probably contains some medieval parts, but has been repaired and modernised several times.
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Two pendulums with the same period fixed on a string act as pair of coupled oscillators. The oscillation alternates between the two. Experimental Setup of Huygens synchronization of two clocks The harmonic oscillator and the systems it models have a single degree of freedom. More complicated systems have more degrees of freedom, for example two masses and three springs (each mass being attached to fixed points and to each other).
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1812 experiments with pendulums Warren was born at Livorno, Italy, the fourth child of Count Henry Hyacinthe de Warren and Christine Walburge de Meuerers. Their ancestors included Guillaume de Warren, first count of Warren and Surrey. He moved to London in 1793 and tried to work as an artist but failed. He then moved to Calcutta on 10 December 1793 and attempted to become an indigo planter but failed.
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The description of the system in terms of the two pendulums is analogous to the flavor basis of neutrinos. These are the parameters that are most easily produced and detected (in the case of neutrinos, by weak interactions involving the W boson). The description in terms of normal modes is analogous to the mass basis of neutrinos. These modes do not interact with each other when the system is free of outside influence.
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The approach used by Huygens also missed some central notions of mathematical physics, which were not lost on others. His work on pendulums came very close to the theory of simple harmonic motion; but the topic was covered fully for the first time by Newton, in Book II of his Principia Mathematica (1687). In 1678 Leibniz picked out of Huygens's work on collisions the idea of conservation law that Huygens had left implicit.
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The simple gravity pendulumdefined by Christiaan Huygens: , Part 4, Definition 3, translated July 2007 by Ian Bruce is an idealized mathematical model of a pendulum. This is a weight (or bob) on the end of a massless cord suspended from a pivot, without friction. When given an initial push, it will swing back and forth at a constant amplitude. Real pendulums are subject to friction and air drag, so the amplitude of their swings declines.
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Synchronized pendulums have been used in clocks and were widely used in gravimeters in the early 20th century. Although Huygens only observed out-of-phase synchronization, recent investigations have shown the existence of in-phase synchronization, as well as "death" states wherein one or both clocks stops.A.L. Fradkov and B. Andrievsky, "Synchronization and phase relations in the motion of two-pendulum system", International Journal of Non-linear Mechanics, vol. 42 (2007), pp. 895–901.
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A sophomore surge (sometimes referred to in the United Kingdom as first-term incumbency bonus) is a term used in the political science of the United States Congress that refers to an increase in votes that congressional candidates (candidates for the House of Representatives) usually receive when running for their first re-election. The phrase has been adopted in Australia by psephologist Malcolm Mackerras who is well known for his electoral pendulums.
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Foucault's pendulum in the Panthéon, Paris Foucault Pendulum at COSI Columbus knocking over a ball The Foucault pendulum or Foucault's pendulum is a simple device named after French physicist Léon Foucault and conceived as an experiment to demonstrate the Earth's rotation. The pendulum was introduced in 1851 and was the first experiment to give simple, direct evidence of the Earth's rotation. Foucault pendulums today are popular displays in science museums and universities.
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Retrieved April 18, 2006. Lawrence Patrick, then a professor at Wayne State University, endured some 400 rides on a rocket sled in order to test the effects of rapid deceleration on the human body. He and his students allowed themselves to be hit in the chest with heavy metal pendulums, impacted in the face by pneumatically driven rotary hammers, and sprayed with shattered glass to simulate window implosion.Roach, Mary (November 19, 1999).
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He described this effect as "odd sympathy". The two pendulum clocks synchronized with their pendulums swinging in opposite directions, 180° out of phase, but in-phase states can also result. Entrainment occurs because small amounts of energy are transferred between the two systems when they are out of phase in such a way as to produce negative feedback. As they assume a more stable phase relationship, the amount of energy gradually reduces to zero.
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Galileo was the first to investigate the timekeeping properties of pendulums, beginning around 1602.His interest was sparked by his discovery that, at least for small swings, the pendulum is isochronous; its period of swing is the same for different size swings. He realized that this property made the pendulum useful for timekeeping. He also discovered that the pendulum's period is dependent on its length, and independent of the mass of the pendulum bob.
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He observed the experiments of Giovanni Battista Baliani regarding falling objects, and he wrote about these experiments noting that two different objects fall in the same amount of time regardless of the medium. He also performed experiments with pendulums and observed that an electrically charged body can attract non-electrified objects. He also noted that two charged objects repelled each other. His observations were published in the works, Philosophia magnetica (1629) and In quatuor libros meteorologicorum Aristotelis commentaria (1646).
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The platform is stabilized by three gyros mounted on it. One measured any rotations about the X axis, one about the Y, and one about the Z axis. They generated signals that were shaped in feedback circuits and sent back to torquers on the inner, middle and outer gimbals that exactly countered the rotations, nulling the gyro outputs and keeping the platform stable. The inner gimbal also carries three accelerometers, two pendulums, and a pair of prisms.
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The accelerometers measured vehicle acceleration along the X, Y, and Z axes. Their outputs were used by the LVDC to measure actual vehicle motion, for the purpose of navigation. The pendulums were used to set the X axis exactly vertical, and the prisms were used to align the Y and Z axes, just before launch. The prisms reflected infrared beams sent into the ST-124 by a theodolite stationed 700 feet away from the launch pad.
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In 1890, B.A. Hjorth & Company agreed to distribute his tools worldwide under the "Bahco" trademark. The Bahco tools became greatly successful, and the company is still in operation and has manufactured over 100 million wrenches to date. Johansson transferred the then-large enterprise to his son, Hannes Brynge, and the B.A. Hjorth & Company in 1916. He started experimenting with electrical armature and in 1919 opened a new factory, Triplex, which manufactured electrical pendulums and various devices.
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A: exterior schematic B: normal temperature C: higher temperature The gridiron pendulum was a temperature-compensated clock pendulum invented by British clockmaker John Harrison around 1726 and later modified by John Ellicott. It was used in precision clocks. In ordinary clock pendulums, the pendulum rod expands and contracts with changes in temperature. The period of the pendulum's swing depends on its length, so a pendulum clock's rate varied with changes in ambient temperature, causing inaccurate timekeeping.
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Pendulums used in Mendenhall gravimeter apparatus, from 1897 scientific journal. The portable gravimeter developed in 1890 by Thomas C. Mendenhall provided the most accurate relative measurements of the local gravitational field of the Earth. A compound pendulum is a body formed from an assembly of particles of continuous shape that rotates rigidly around a pivot. Its moment of inertia is the sum of the moments of inertia of each of the particles that it is composed of.
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It swings back and forth, with a precisely constant time interval between each swing, called the beat. A pendulum movement has a pendulum hangar usually attached to a sturdy support on the back, from which the pendulum is suspended and a fork which gives the pendulum impulses. The oscillator always has some means for adjusting the rate of the clock. Pendulums usually have an adjustment nut under the bob, while balance wheels have a regulator lever on the balance spring.
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The basic physics behind neutrino oscillation can be found in any system of coupled harmonic oscillators. A simple example is a system of two pendulums connected by a weak spring (a spring with a small spring constant). The first pendulum is set in motion by the experimenter while the second begins at rest. Over time, the second pendulum begins to swing under the influence of the spring, while the first pendulum's amplitude decreases as it loses energy to the second.
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Momentum was originally commissioned by the Barbican Centre for its unique 90m long Curve gallery. It was the first in a series of kinetic sculptures created by the studio. Using light, sound, and movement UVA transformed the Curve into a spatial instrument, installing a sequence of pendulum-like elements throughout the gallery to create an evolving composition of light and sound. The pendulums projected shadows and planes of light across the 6 metre-high walls and curved floor of the space.
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Each traction motor weighs , and the entire bogie weighs in at about . The entire traction drive is mounted on an assisting beam in the center of the bogie, and attached to the outer sides via two pendulums. It is possible to mount in the center, since the bogies do not have pivot pins; the bogie is propped up above the frame by eight flexicoil springs. The resulting freedom of movement in all directions is limited by hydraulic buffers and rubber elements.
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307 In 1687, Isaac Newton in Principia Mathematica showed that this was because the Earth was not a true sphere but slightly oblate (flattened at the poles) from the effect of centrifugal force due to its rotation, causing gravity to increase with latitude.Lenzen & Multauf, 1964, p.307 Portable pendulums began to be taken on voyages to distant lands, as precision gravimeters to measure the acceleration of gravity at different points on Earth, eventually resulting in accurate models of the shape of the Earth.
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Mercury pendulum in Howard astronomical regulator clock, 1887 The largest source of error in early pendulums was slight changes in length due to thermal expansion and contraction of the pendulum rod with changes in ambient temperature.Matthys 2004, p.3 This was discovered when people noticed that pendulum clocks ran slower in summer, by as much as a minute per week (one of the first was Godefroy Wendelin, as reported by Huygens in 1658)., translation by Ernest L. Edwardes (December 1970) Antiquarian Horology, Vol.
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He learned that the human skull can withstand up to one and a half tons for one second before experiencing any type of damage. In an article written by Albert King PhD, it was approximated that improvements made to cars since cadaver testing have prevented 143,000 injuries and 4250 deaths. Miniature accelerometers are placed on the bone of the tested area of the cadaver. Damage is then inflicted on the cadaver with different tools including; linear impactors, pendulums, or falling weights.
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The professor taught him that no two clocks could be made to run synchronously independent on their own to where they ran at exactly the same time on the same beat and swing of the pendulums. He explained that the only way to arrive at the correct time was to use fixed stars. The stars could be seen by the use of a transit telescope. In 1889 Johnson bought one so he could observe stars in getting accurate readings for time measurements.
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The importance of the escapement in the history of technology is that it was the key invention that made the all-mechanical clock possible. The invention of the first all-mechanical escapement, the verge escapement, in 13th-century Europe initiated a change in timekeeping methods from continuous processes, such as the flow of water in water clocks, to repetitive oscillatory processes, such as the swing of pendulums, which could yield more accuracy. Oscillating timekeepers are used in every modern clock.
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Pendulums used in Mendenhall gravimeter apparatus, from 1897 scientific journal. The portable gravimeter developed in 1890 by Thomas C. Mendenhall provided the most accurate relative measurements of the local gravitational field of the Earth. The mass of Earth is measured indirectly by determining other quantities such as Earth's density, gravity, or gravitational constant. The first measurement in the 1770s Schiehallion experiment resulted in a value about 20% too low. The Cavendish experiment of 1798 found the correct value within 1%.
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This method became general throughout the United States and Canada. Mendenhall Gravimeter Pendulums He became professor at the U.S. Signal Corps in 1884, introducing of systematic observations of lightning, and investigating methods for determining ground temperatures. He was the first to establish stations in the United States for the systematic observation of earthquake phenomena. Resigning in 1886, Mendenhall took up the presidency of the Rose Polytechnic Institute in Terre Haute, Indiana before becoming superintendent of the U.S. Coast and Geodetic Survey in 1889.
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Observation that pendulum clocks slowed down in summer brought the realization that thermal expansion and contraction of the pendulum rod with changes in temperature was a source of error. This was solved by the invention of temperature-compensated pendulums; the mercury pendulum by George Graham in 1721 and the gridiron pendulum by John Harrison in 1726.Milham 1945, pp. 193–195 With these improvements, by the mid-18th century precision pendulum clocks achieved accuracies of a few seconds per week.
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The direction the plane rotated depended on the direction that the ball rotated.)Tom Holmberg, "Artillery Swings Like a Pendulum..." in "The Napoleon Series"Steele, Brett D. (April 1994) "Muskets and pendulums: Benjamin Robins, Leonhard Euler, and the ballistics revolution," Technology and Culture, vol. 35, no. 2, pages 348–382.Newton's and Robins' observations of the Magnus effect are reproduced in: Peter Guthrie Tait (1893) " On the path of a rotating spherical projectile," Transactions of the Royal Society of Edinburgh, vol.
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In 1885, working as an assistant at the University of Karlsruhe, Rebeur-Paschwitz became interested in Friedrich Zöllner’s pendulum. In 1886, he started construction of a horizontal pendulum at the astronomical observatory of Karlsruhe with the idea to measure oscillations of the plumb line resulting from the influence of astronomical bodies. However, his pendulums appeared to be sensitive also to horizontal accelerations of the ground. Rebeur-Paschwitz became the first person to continuously record movements of the ground on photographic paper.
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Following more verbal arguments with Dick, HouseGuests Jen and Kail contemplated walking from the game; the two ultimately decided to stay. On Day 34, Nick became the fourth HouseGuest to be evicted from the house in a vote of six to two. Following Nick's eviction, HouseGuests competed in the "Times Up" endurance Head of Household competition. For this competition, HouseGuests were required to hang upside down on rocking pendulums; when a player fell off of their pendulum, they were eliminated from the competition.
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All of Our Names is an album by Canadian singer-songwriter Sarah Harmer, released in 2004. It peaked at number 6 on the Top Canadian Albums chart and number 43 on the Billboard Top Heatseekers chart. "Almost" b/w "Pendulums" was released as a single with "Almost" reaching the top 20 on Canadian pop charts. A different version of the track "Silver Road", recorded with The Tragically Hip and for the soundtrack for the film Men with Brooms had been previously released as a single in 2003.
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Made in Germany, 1591 An equation clock is a mechanical clock which includes a mechanism that simulates the equation of time, so that the user can read or calculate solar time, as would be shown by a sundial. The first accurate clocks, controlled by pendulums, were patented by Christiaan Huyghens in 1657. For the next few decades, people were still accustomed to using sundials, and wanted to be able to use clocks to find solar time. Equation clocks were invented to fill this need.
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To avoid the need for a very large case, most clocks using the verge escapement had a short pendulum. The anchor mechanism, however, reduced the pendulum's necessary swing to between 4° to 6°, allowing clockmakers to use longer pendulums with consequently slower beats. These required less power to move, caused less friction and wear, and were more accurate than their shorter predecessors. Most longcase clocks use a pendulum about a metre (39 inches) long to the center of the bob, with each swing taking one second.
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Following a more abstract vein, Roepstorff's mobiles, and the use of brass in general, hint a mythical dimension, hovering about cosmic vibrations. Algebraic in their language and with pure forms reminiscent of beings as water, suns and the two-legged, the mobiles suggest a wholeness. Assembled as pendulums the structures themselves are reliant on principles of balance. As a very recent string in a versatile practice, Roepstorff's "waterings" also indicates a layered process, a long repeated application of water and pigment often lasting for months.
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Italian scientist Galileo Galilei was the first to study the properties of pendulums, beginning around 1602. The earliest extant report of his research is contained in a letter to Guido Ubaldo dal Monte, from Padua, dated November 29, 1602. His biographer and student, Vincenzo Viviani, claimed his interest had been sparked around 1582 by the swinging motion of a chandelier in Pisa Cathedral.La Lampada di Galileo, by Francesco Malaguzzi Valeri, for Archivio storico dell'arte, Volume 6 (1893); Editor, Domenico Gnoli; Publisher Danesi, Rome; Page 215-218.
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The Foucault pendulum in 1851 was the first demonstration of the Earth's rotation that did not involve celestial observations, and it created a "pendulum mania". In this animation the rate of precession is greatly exaggerated. During the 18th and 19th century, the pendulum clock's role as the most accurate timekeeper motivated much practical research into improving pendulums. It was found that a major source of error was that the pendulum rod expanded and contracted with changes in ambient temperature, changing the period of swing.
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The most accurate commercially produced pendulum clock was the Shortt-Synchronome free pendulum clock, invented in 1921.Milham 1945, p.615 Its Invar master pendulum swinging in a vacuum tank had a Q of 110,000 and an error rate of around a second per year. Their Q of 103–105 is one reason why pendulums are more accurate timekeepers than the balance wheels in watches, with Q around 100–300, but less accurate than the quartz crystals in quartz clocks, with Q of 105–106.
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Finally, in 1854, Airy got the value by measurements in a coal mine in Harton, Sunderland. Airy's method assumed that the Earth had a spherical stratification. Later, in 1883, the experiments conducted by Robert von Sterneck (1839 to 1910) at different depths in mines of Saxony and Bohemia provided the average density values ρ between 5.0 and . This led to the concept of isostasy, which limits the ability to accurately measure ρ, by either the deviation from vertical of a plumb line or using pendulums.
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In retirement, Woodward wrote another classic book, My Own Right Time fondly known as MORT, a record of his passion for horology. Along with many other topics, MORT describes in detail the design of his clocks, including his masterpiece W5. Woodward contributed dozens of articles to horological periodicals over more than 30 years. From his experience as a mathematician and analyst of complex systems, he has made major contributions to scientific horology, including the definitive analysis of balance springs and much work on the properties of pendulums.
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These two functions both disturb the pendulum's motion. The advantages of the Shortt clock are first, it reduced the disturbance of the primary pendulum due to the impulse by only giving the pendulums an impulse once every 30 seconds exactly (30 pendulum swings), and second, it eliminated all other interaction with the primary pendulum by generating the necessary precise timing signal to control the secondary clock (and record the passage of time) from the impulse mechanism itself, leaving the pendulum to swing "free" of interference.
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A zero-length spring is a spring supported in such a way that its exerted force is proportional to its length, rather than the distance it is compressed. That is, over at least part of its travel, it does not conform to Hooke's Law of spring compression. The zero-length spring is extremely important to seismometers and gravimeters because it permits the design of vertical pendulums with (theoretically) infinite periods. In practice, periods of a thousand seconds are possible, a hundredfold increase from other forms of pendulum.
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In 1821, with the help of Frederik VI of Denmark, he founded a company in Altona to produce precision watches – this company later became Theodor Knoblich and existed until 1991. Kessels worked on the development of marine chronometers, observation clocks and pendulums for astronomical observatories. He also continued to represent Breguet in northern Germany and Scandinavia and seems to have worked with the British chronometer maker George Muston. In total, 200 to 250 precision watches can be attributed to Kessels, an average of eight per year.
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Accurate time has become ubiquitous and its maintenance a branch of information and communications technology. A century ago none of this existed, and the world depended on the pendulum clock to keep its time, referenced to astronomical observations. There was a scientific literature on the behaviour of pendulums and clocks; and a widespread craft-based industry making timepieces; but it could not be said that horology was a branch of engineering. Robertson became Professor of Electrical Engineering in Merchant Venturer’s Technical College in 1902.
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On June 12, a helicopter flew a yellow rope across the canyon. The rope was attached to the steel high-wire and a giant winch was used to slowly pull the wire across as the crew slowly increased tension to support the increasing weight. Weighted pendulums were attached every to keep the wire from twisting. To make the walk accessible to viewers worldwide, it was held after dark, with the first step coming at 10:16 p.m. local time (02:16 June 16 UTC).
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One of the most remarkable of Airy's researches was his determination of the mean density of the Earth. In 1826, the idea occurred to him of attacking this problem by means of pendulum experiments at the top and bottom of a deep mine. His first attempt, made in the same year, at the Dolcoath mine in Cornwall, failed in consequence of an accident to one of the pendulums. A second attempt in 1828 was defeated by a flooding of the mine, and many years elapsed before another opportunity presented itself.
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In the flat response mode, the LP seismometers had a natural period of 15 s. In the peaked-response mode, they acted as underdamped pendulums with a natural period of 2.2 s. Sensitivity to ground motion peaked sharply at 0.45 Hz in peaked response mode with a useful frequency range of 0.004 to 2 Hz. Maximum sensitivity was enhanced by a factor of 5.6 in the peaked response mode, but sensitivity to low-frequency signals was reduced. All seismometers could detect ground motions as small as 0.3 nm.
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The LP seismometers could function in a flat-response mode and in a peaked response mode. In the flat response mode, the LP seismometers had a natural period of 15 s. In the peaked-response mode, they acted as underdamped pendulums with a natural period of 2.2 s. Sensitivity to ground motion peaked sharply at 0.45 Hz in peaked response mode with a useful frequency range of 0.004 to 2 Hz. Maximum sensitivity was enhanced by a factor of 6 in the peaked response mode, but sensitivity to low-frequency signals was reduced.
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The timekeeping elements in all clocks, which include pendulums, balance wheels, the quartz crystals used in quartz watches, and even the vibrating atoms in atomic clocks, are in physics called harmonic oscillators. The reason harmonic oscillators are used in clocks is that they vibrate or oscillate at a specific resonant frequency or period and resist oscillating at other rates. However, the resonant frequency is not infinitely 'sharp'. Around the resonant frequency there is a narrow natural band of frequencies (or periods), called the resonance width or bandwidth, where the harmonic oscillator will oscillate. p.
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Also, another error caused by the finite diameter of the pivot knife edges could be made to cancel out by interchanging the knife edges. Bessel didn't construct such a pendulum, but in 1864 Adolf Repsold, under contract to the Swiss Geodetic Commission, developed a symmetric pendulum 56 cm long with interchangeable pivot blades, with a period of about ¾ second. The Repsold pendulum was used extensively by the Swiss and Russian Geodetic agencies, and in the Survey of India. Other widely used pendulums of this design were made by Charles Peirce and C. Defforges.
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The realization that only small pendulum swings were nearly isochronous motivated clockmakers to design escapements with small swings. The chief advantage of the anchor was that by locating the pallets farther from the pivot, the swing of the pendulum was reduced from around 100° in verge clocks to only 4°-6°. In addition to the improved accuracy due to isochronism, this allowed clocks to use longer pendulums, which had a slower 'beat'. Lower air drag meant they needed less power to keep swinging, and caused less wear on the clock's movement.
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Shilovsky's gyrocar in 1914, London A gyrocar is a two-wheeled automobile. The difference between a bicycle or motorcycle and a gyrocar is that in a bike, dynamic balance is provided by the rider, and in some cases by the geometry and mass distribution of the bike itself, and the gyroscopic effects from the wheels. Steering a motorcycle is done by precessing the front wheel. In a gyrocar, balance was provided by one or more gyroscopes, and in one example, connected to two pendulums by a rack and pinion.
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During the battery of tests, she was not engrossed because it appeared that the "concept of test, or sharing an experience or situation, seemed foreign to her." On the Binet test, she read excellently, finishing the ten-year Binet fire story in 33 seconds with no errors, but when asked to recall anything from the story she read, Barbara failed to reproduce any from her memory. After repeated questions or commands, she complied almost immediately. Barbara frequently referred to "motor transports" and "piggy- back," and was fascinated with appendages, such as pendulums and smoke stacks.
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Human legs during walking have been mechanically simplified in previous studies to a set of inverted pendulums, while distance running (characterized as a bouncing gait) has modeled the legs as springs. Until recently, it had been long believed that faster sprinting speeds are promoted solely by physiological features that increase stride length and frequency; while these factors do contribute to sprinting velocities, it has also been found that the runner's ability to produce ground forces is also very important. Weyand et al. (2000) Weyand, Peter G., Deborah B. Sternlight, Matthew J. Bellizzi, and Seth Wright.
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Meli 2006 (pp. 131-134); Heilbron 1999 (pp.180-181). With pendulums to keep time (sometimes augmented by a chorus of Jesuits chanting in time with a pendulum to provide an audible timer) and a tall structure in the form of Bologna's Torre de Asinelli from which to drop objects, Riccioli was able to engage in precise experiments with falling bodies. He verified that falling bodies followed Galileo's "odd-number" rule so that the distance travelled by a falling body increases in proportion to the square of the time of fall, indicative of constant acceleration.
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Lantern clocks were produced in vast numbers during the decades before the pioneering invention of the pendulum by the Dutch scientist Christiaan Huygens in 1656. Before this invention, lantern clocks used a balance wheel lacking a balance spring for their timekeeping element, which limited their accuracy to perhaps 15 minutes per day. Shortly after Huygens' invention, the bob pendulum was introduced in England, and most English clockmakers adopted the new system quickly. The pendulum increased the accuracy of clocks so greatly that many existing clocks were converted, with pendulums being added at the back.
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The towers have a suspended structure; the building consists of two pillars together on top of a platform from which hang two large towers with perimeter beams six feet singing with pendulums each floor with cable-stayed steel cables. Construction commenced with the concrete footings, the two central pillars and the upper platform. Then the towers were built from top to bottom, from the upper platform plant to plant closer to the base of the building. At the base, three floors (six floors including basements) were built from the bottom up.
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Some items can be combined by selecting them one after the other, such as a candelabra and lighter that will illuminate a dark passage. Other items for working out puzzles include weapons like a knife and a gun. However, the mansion in Doctor Hauzer features no combat or enemies and instead relies upon numerous traps and obstacles that can cause the player an instant game over. These include floor pits in numerous areas, a room filled with swinging blades on pendulums, and a hallway containing a large, rolling boulder.
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Persoz pendulum device The pendulum consists of balls which rest on the coating under test and form the fulcrum. The Persoz pendulum is very similar to the Konig pendulum. Both employ the same principle, that is the softer the coating the more the pendulum oscillations are damped and the shorter the time needed for the amplitude of oscillation to be reduced by a specified amount. The two pendulums differ in shape, mass and oscillation time, and there is no general relationship between the results obtained using the two pieces of equipment.
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The theory of Daniel Bernoulli was opposed also by Jean le Rond d'Alembert. When generalizing the theory of pendulums of Jacob Bernoulli he discovered a principle of dynamics so simple and general that it reduced the laws of the motions of bodies to that of their equilibrium. He applied this principle to the motion of fluids, and gave a specimen of its application at the end of his Dynamics in 1743. It was more fully developed in his Traité des fluides, published in 1744, in which he gave simple and elegant solutions of problems relating to the equilibrium and motion of fluids.
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Herschel returned to England on furlough in late 1873, where he worked on collecting his late father's letters into mid–1874. He was promoted to major on 10 March 1876. In April 1882 he arrived in the United States, where he spent a year working with Charles Sanders Peirce on the construction of pendulums to conduct gravimetric and geodesic surveys on behalf of the United States Coast and Geodetic Survey. Herschel eventually became the Deputy Superintendent of Trigonometrical Survey, before eventually retiring from the army on 10 March 1886 as a major and brevet lieutenant-colonel, with the honorary rank of colonel.
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A pendulum the length of the Earth's radius is impractical, so Schuler tuning doesn't use physical pendulums. Instead, the electronic control system of the inertial navigation system is modified to make the platform behave as if it were attached to a pendulum. The inertial platform is mounted on gimbals, and an electronic control system keeps it pointed in a constant direction with respect to the three axes. As the vehicle moves, the gyroscopes detect changes in orientation, and a feedback loop applies signals to torquers to rotate the platform on its gimbals to keep it pointed along the axes.
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In 1660, Viviani and Giovanni Alfonso Borelli conducted an experiment to determine the speed of sound. Timing the difference between the seeing the flash and hearing the sound of a cannon shot at a distance, they calculated a value of 350 meters per second (m/s), considerably better than the previous value of 478 m/s obtained by Pierre Gassendi. The currently accepted value is 331.29 m/s at 0 °C or 340.29 m/s at sea level. It has also been claimed that in 1661 he experimented with the rotation of pendulums, 190 years before the famous demonstration by Foucault.
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By geometrical methods which were an early use of calculus, he showed it to be a cycloid, rather than the circular arc of a pendulum's bob, and therefore that pendulums are not isochronous. He also solved a problem posed by Mersenne: how to calculate the period of a pendulum made of an arbitrarily-shaped swinging rigid body. This involved discovering the centre of oscillation and its reciprocal relationship with the pivot point. In the same work, he analysed the conical pendulum, consisting of a weight on a cord moving in a circle, using the concept of centrifugal force.
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Viviani, 1892, Tito Lessi Dome of the Cathedral of Pisa with the "lamp of Galileo" Galileo's theoretical and experimental work on the motions of bodies, along with the largely independent work of Kepler and René Descartes, was a precursor of the classical mechanics developed by Sir Isaac Newton. Galileo conducted several experiments with pendulums. It is popularly believed (thanks to the biography by Vincenzo Viviani) that these began by watching the swings of the bronze chandelier in the cathedral of Pisa, using his pulse as a timer. Later experiments are described in his Two New Sciences.
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In Kater's time, the period T of pendulums could be measured very precisely by timing them with precision clocks set by the passage of stars overhead. Prior to Kater's discovery, the accuracy of g measurements was limited by the difficulty of measuring the other factor L, the length of the pendulum, accurately. L in equation (1) above was the length of an ideal mathematical 'simple pendulum' consisting of a point mass swinging on the end of a massless cord. However the 'length' of a real pendulum, a swinging rigid body, known in mechanics as a compound pendulum, is more difficult to define.
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In 1998, Bandai released a follow-up virtual pet series known as Pendulums which features higher evolution levels and is the first to introduce the Jogress function which enable combination between certain type of digimons. The pendulum is used to count the number of times the device has been shaken. Five versions of the Digimon Pendulum were released which is Nature Spirit for version 1, Deep Savers for version 2, Nightmare Soldier for version 3, Wind Guardian for version 4 and finally Metal Empire for version 5. Each of these being followed by a 0.5 version which contained a slightly- altered character lineup.
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The Riefler escapement, used in Clemens-Riefler regulator clocks was accurate to 10 milliseconds per day. Electromagnetic escapements, which used a switch or phototube to turn on a solenoid electromagnet to give the pendulum an impulse without requiring a mechanical linkage, were developed. The most accurate pendulum clock was the Shortt-Synchronome clock, a complicated electromechanical clock with two pendulums developed in 1923 by W.H. Shortt and Frank Hope-Jones, which was accurate to better than one second per year. A slave pendulum in a separate clock was linked by an electric circuit and electromagnets to a master pendulum in a vacuum tank.
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Galileo had the idea for a pendulum clock in 1637, which was partly constructed by his son in 1649, but neither lived to finish it.A modern reconstruction can be seen at The introduction of the pendulum, the first harmonic oscillator used in timekeeping, increased the accuracy of clocks enormously, from about 15 minutes per day to 15 seconds per day, p.3, also published in Proceedings of the Royal Society of London, A 458, 563–579 leading to their rapid spread as existing 'verge and foliot' clocks were retrofitted with pendulums. A lantern clock that has been converted to use a pendulum.
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Elephants can move both forwards and backwards, but cannot trot, jump, or gallop. They use only two gaits when moving on land: the walk and a faster gait similar to running. In walking, the legs act as pendulums, with the hips and shoulders rising and falling while the foot is planted on the ground. With no "aerial phase", the fast gait does not meet all the criteria of running, although the elephant uses its legs much like other running animals, with the hips and shoulders falling and then rising while the feet are on the ground.
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Entrainment has been used to refer to the process of mode locking of coupled driven oscillators, which is the process whereby two interacting oscillating systems, which have different periods when they function independently, assume a common period. The two oscillators may fall into synchrony, but other phase relationships are also possible. The system with the greater frequency slows down, and the other speeds up. Dutch physicist Christiaan Huygens, the inventor of the pendulum clock, introduced the concept after he noticed, in 1666, that the pendulums of two clocks mounted on a common board had synchronized, and subsequent experiments duplicated this phenomenon.
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A green ballistic pendulum Animation of a ballistic pendulum A ballistic pendulum is a device for measuring a bullet's momentum, from which it is possible to calculate the velocity and kinetic energy. Ballistic pendulums have been largely rendered obsolete by modern chronographs, which allow direct measurement of the projectile velocity. Although the ballistic pendulum is considered obsolete, it remained in use for a significant length of time and led to great advances in the science of ballistics. The ballistic pendulum is still found in physics classrooms today, because of its simplicity and usefulness in demonstrating properties of momentum and energy.
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Timothy Mason longcase clock movement with striking mechanism, circa 1730 The anchor mechanism reduced the pendulum's swing to around 4° to 6°, allowing clockmakers to use longer pendulums, which had slower "beats". These consumed less power allowing clocks to run longer between windings, caused less friction and wear in the movement, and were more accurate. Almost all longcase clocks use a seconds pendulum (also called a "Royal" pendulum) meaning that each swing (or half-period) takes one second. These are about a metre (39 inches) long (to the centre of the bob), requiring a long narrow case.
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Giovanni Battista RiccioliAlso "Giambattista" and "Giovambattista" (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order. He is known, among other things, for his experiments with pendulums and with falling bodies, for his discussion of 126 arguments concerning the motion of the Earth, and for introducing the current scheme of lunar nomenclature. He is also widely known for discovering the first double star. He argued that the rotation of the Earth should reveal itself because on a rotating Earth, the ground moves at different speeds at different times.
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Observation of Foucault pendulums, popular in science museums around the world, demonstrate both that the world is spherical and that it rotates (not that the stars are rotating around it). The mathematics of navigation by GPS assume that satellites are moving in known orbits around an approximately spherical surface. The accuracy of GPS navigation in determining latitude and longitude and the way these numbers map onto locations on the ground show that these assumptions are correct. The same is true for the operational GLONASS system run by Russia, and the in-development European Galileo, Chinese BeiDou, and Indian IRNSS.
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Torsion clocks are capable of running much longer between windings than clocks with an ordinary pendulum, because the torsion pendulum rotates slowly and takes little energy. However they are difficult to set up and are usually not as accurate as clocks with ordinary pendulums. One reason is that the oscillation period of the torsion pendulum changes with temperature due to temperature-dependent change in elasticity of the spring. The rate of the clock can be made faster or slower by an adjustment screw mechanism on the torsion pendulum that moves the weight balls in or out from the axis.
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They are based on the Hahn spin echo technique of applying periodic pulses to enable refocusing and hence extend the coherence times of qubits. Periodic repetition of suitable high-order DD sequences may be employed to engineer a ‘stroboscopic saturation’ of qubit coherence, or coherence plateau, that can persist in the presence of realistic noise spectra and experimental control imperfections. This permits device-independent, high-fidelity data storage for computationally useful periods with bounded error probability. Dynamical decoupling has also been studied in a classical context for two coupled pendulums whose oscillation frequencies are modulated in time.
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An Asian elephant walking Elephants can move both forwards and backwards, but cannot trot, jump, or gallop. They use only two gaits when moving on land, the walk and a faster gait similar to running. In walking, the legs act as pendulums, with the hips and shoulders rising and falling while the foot is planted on the ground. With no "aerial phase", the fast gait does not meet all the criteria of running, although the elephant uses its legs much like other running animals, with the hips and shoulders falling and then rising while the feet are on the ground.
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Bakewell's improved facsimile 1848 Bakewell's "image telegraph" had many of the features of modern facsimile machines, and replaced the pendulums of Bain's system with synchronized rotating cylinders. The system involved writing or drawing on a piece of metal foil with a special insulating ink; the foil was then wrapped around a cylinder which slowly rotated, driven by a clock mechanism. A metal stylus driven by a screw thread traveled across the surface of the cylinder as it turned, tracing out a path over the foil. Each time the stylus crossed the insulating ink, the current through the foil to the stylus was interrupted.
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Pendulums in clocks (see example at right) are usually made of a weight or bob (b) suspended by a rod of wood or metal (a). To reduce air resistance (which accounts for most of the energy loss in precision clocks) the bob is traditionally a smooth disk with a lens-shaped cross section, although in antique clocks it often had carvings or decorations specific to the type of clock. In quality clocks the bob is made as heavy as the suspension can support and the movement can drive, since this improves the regulation of the clock (see Accuracy below). A common weight for seconds pendulum bobs is .
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Around 1900 low-thermal-expansion materials began to be used for pendulum rods in the highest precision clocks and other instruments, first invar, a nickel steel alloy, and later fused quartz, which made temperature compensation trivial. Precision pendulums were housed in low pressure tanks, which kept the air pressure constant to prevent changes in the period due to changes in buoyancy of the pendulum due to changing atmospheric pressure. The best pendulum clocks achieved accuracy of around a second per year. The timekeeping accuracy of the pendulum was exceeded by the quartz crystal oscillator, invented in 1921, and quartz clocks, invented in 1927, replaced pendulum clocks as the world's best timekeepers.
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The perceived harmony (consonance) of two such notes would be explained if the ratio of the air oscillation frequencies is also 1 : 2, which in turn is consistent with the source-air-motion-frequency-equivalence hypothesis. He also performed extensive experiments to determine the acceleration of falling objects by comparing them with the swing of pendulums, reported in his Cogitata Physico-Mathematica in 1644. He was the first to measure the length of the seconds pendulum, that is a pendulum whose swing takes one second, and the first to observe that a pendulum's swings are not isochronous as Galileo thought, but that large swings take longer than small swings.
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The pulse from the primary pendulum was used to keep the secondary pendulum in phase with it through a device called a "hit and miss synchronizer". Every 30 swings, after the primary pendulum was impulsed, the position of the two pendulums was compared. This was done by an electrical pulse from the second circuit, activated by the primary pendulum's gravity lever, which used a second electromagnet in the secondary unit to move a vane into the path of a leaf spring attached to the secondary pendulum. If the secondary pendulum lagged behind the primary, the spring would catch on the vane (called a "hit").
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Resonance occurs when the frequency of the external force (applied) is the same as the natural frequency (resonant frequency) of the system. When such a situation occurs, the external force always acts in the same direction as the motion of the oscillating object, with the result that the amplitude of the oscillation increases indefinitely, as it's shown in the adjacent diagram. Away from the value of resonant frequency, either greater or lesser, the amplitude of the corresponding frequency is smaller. In a set of driving pendulums with different length of strings hanging objects, the one pendulum with the same length of string as the driver gets the biggest amplitude of swinging.
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Hipp also invented a small motor and built the chronoscope and the registering chronograph for time measurement. The first electric clocks had prominent pendulums because this was a familiar shape and design. Smaller clocks and watches with a spiral-balance are made on the same principles as pendulum clocks. In 1918, Henry Ellis Warren invented the first synchronous electric clock in Ashland, MA, which kept time from the oscillations of the power grid.U.S. patent #1283434 Warren, Henry E. Timing device, filed February 26, 1917, issued October 29, 1918, on Google Patents In 1931, the Synclock was the first commercial synchronous electric clock sold in the UK.
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The viscosity of the air through which the pendulum swings will vary with atmospheric pressure, humidity, and temperature. This drag also requires power that could otherwise be applied to extending the time between windings. Traditionally the pendulum bob is made with a narrow streamlined lens shape to reduce air drag, which is where most of the driving power goes in a quality clock. In the late 19th century and early 20th century, pendulums for precision regulator clocks in astronomical observatories were often operated in a chamber that had been pumped to a low pressure to reduce drag and make the pendulum's operation even more accurate by avoiding changes in atmospheric pressure.
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Large Newton's cradle at American Science and Surplus Christiaan Huygens used pendulums to study collisions. His work, De Motu Corporum ex Percussione (On the Motion of Bodies by Collision) published posthumously in 1703, contains a version of Newton's first law and discusses the collision of suspended bodies including two bodies of equal mass with the motion of the moving body being transferred to the one at rest. The principle demonstrated by the device, the law of impacts between bodies, was first demonstrated by the French physicist Abbé Mariotte in the 17th century.Wikisource:Catholic Encyclopedia (1913)/Edme Mariotte Newton acknowledged Mariotte's work, among that of others, in his Principia.
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The first system to supplant ballistic pendulums with direct measures of projectile speed was invented in 1808, during the Napoleonic Wars and used a rapidly rotating shaft of known speed with two paper disks on it; the bullet was fired through the disks, parallel to the shaft, and the angular difference in the points of impact provided an elapsed time over the distance between the disks. A direct electromechanical clockwork measure appeared in 1848, with a spring-driven clock started and stopped by electromagnets, whose current was interrupted by the bullet passing through two meshes of fine wires, again providing the time to traverse the given distance.
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He co-edited the book series published by the Institute of Public Administration of Canada. Aucoin himself was a prolific writer, authoring and editing fifteen books and eighty articles and book chapters. His article "Administrative Reform in Public Management: Paradigms, Principles, Paradoxes and Pendulums" in the journal Governance is a highly cited and seminal article describing New Public Management reforms. His 2011 book Democratizing the Constitution: Reforming Responsible Government, co-authored with Mark D. Jarvis and Lori Turnbull, received the 2011 Donner Prize rewarding excellence and innovation in public policy writing by Canadians as well as the Donald Smiley Prize from the Canadian Political Science Association.
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In the examples, the pendulums are of great size to aid in the visualization of the pendulum swing in relation to the Earth (shown as blue circles). The pendulum is drawn so that 90 degrees of pendulum arc sweeps out 90 degrees of arc on the surface of the Earth. Views from the side, the front, and above (right, center, left) are provided to aid in the interpretation of the diagrams and arrows are provided to show the direction of the Earth's rotation. The schematic at the bottom of the each figure represents the range of swing of the pendulum as viewed from above and normalized to a standard orientation.
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When correctly adjusted and set in motion, it exhibits a curious motion in which periods of purely rotational oscillation gradually alternate with periods of purely up and down oscillation. The energy stored in the device shifts slowly back and forth between the translational 'up and down' oscillation mode and the torsional 'clockwise and counterclockwise' oscillation mode, until the motion eventually dies away. Despite the name, in normal operation it does not swing back and forth as ordinary pendulums do. The mass usually has opposing pairs of radial 'arms' sticking out horizontally, threaded with small weights that can be screwed in or out to adjust the moment of inertia to 'tune' the torsional vibration period.
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Some movements are aperiodic, others regular, as the Earth tides caused by the lunar and solar gravitational field. The pendulums measure a distance of 95 m between the upper and lower mountings, which contributes to the fact that the instruments detect tectonic movements with high precision and are relatively immune to some of the noise which affects smaller instruments. The Earth's crust is the outer brittle layer of our planet, on average thick in continental areas. This moves up and down by ten centimeters during the time of 12 and 24 hours due to the attraction of Moon and Sun, and is accompanied by a local tilting of some parts in a billion of radians.
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Horologium oscillatorium sive de motu pendulorum, 1673 Huygens developed the oscillating timekeeping mechanisms that have been used ever since in mechanical watches and clocks, the balance spring and the pendulum, leading to a great increase in timekeeping accuracy. In 1656, inspired by earlier research into pendulums by Galileo Galilei, he invented the pendulum clock, which was a breakthrough in timekeeping and became the most accurate timekeeper for the next 275 years until the 1930s. Huygens contracted the construction of his clock designs to Salomon Coster in The Hague, who built the clock. The pendulum clock was much more accurate than the existing verge and foliot clocks and was immediately popular, quickly spreading over Europe.
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The presence of the acceleration of gravity g in the periodicity equation (1) for a pendulum means that the local gravitational acceleration of the Earth can be calculated from the period of a pendulum. A pendulum can therefore be used as a gravimeter to measure the local gravity, which varies by over 0.5% across the surface of the Earth.The value of "g" (acceleration due to gravity) at the equator is 9.780 m/s2 and at the poles is 9.832 m/s2, a difference of 0.53%. The pendulum in a clock is disturbed by the pushes it receives from the clock movement, so freeswinging pendulums were used, and were the standard instruments of gravimetry up to the 1930s.
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These were vulnerable to damage or destruction over the years, and because of the difficulty of comparing prototypes, the same unit often had different lengths in distant towns, creating opportunities for fraud. During the Enlightenment scientists argued for a length standard that was based on some property of nature that could be determined by measurement, creating an indestructible, universal standard. The period of pendulums could be measured very precisely by timing them with clocks that were set by the stars. A pendulum standard amounted to defining the unit of length by the gravitational force of the Earth, for all intents constant, and the second, which was defined by the rotation rate of the Earth, also constant.
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Although Galileo seriously considered the priesthood as a young man, at his father's urging he instead enrolled in 1580 at the University of Pisa for a medical degree. In 1581, when he was studying medicine, he noticed a swinging chandelier, which air currents shifted about to swing in larger and smaller arcs. To him, it seemed, by comparison with his heartbeat, that the chandelier took the same amount of time to swing back and forth, no matter how far it was swinging. When he returned home, he set up two pendulums of equal length and swung one with a large sweep and the other with a small sweep and found that they kept time together.
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Primary pendulum tank A pendulum swinging in a vacuum without friction, at a constant amplitude free of external disturbances, theoretically keeps perfect time. However, pendulums in clocks have to be linked to the clock's mechanism, which disturbs their natural swing, and this was the main cause of error in precision clocks of the early 20th century. An ordinary clock's mechanism interacts with the pendulum each swing to perform two functions: first, the pendulum must activate some kind of linkage to record the passage of time. Second, the clock's mechanism, triggered by the linkage, must give the pendulum a push (impulse) to replace the energy the pendulum loses to friction, to keep it swinging.
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The primary and secondary pendulums were linked together in a feedback loop which kept the secondary synchronized with the primary. The secondary clock had a mechanical escapement using a 15-tooth count wheel which was moved forward each right-hand pendulum swing by a pawl attached to the pendulum. Every 15 oscillations (30 seconds), this escapement released a gravity lever which gave the secondary pendulum a push. As it fell, the secondary pendulum's gravity lever closed a switch which activated an electromagnet that reset (raised) the secondary pendulum gravity lever and also sent a pulse of current to an electromagnet in the primary unit which released a second gravity lever to give the primary pendulum a push.
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Warren was acting director at the Madras Observatory from February 1805 to October 1811 and in this period he established the longitude of Madras, a figure that was used in the trigonometrical survey and for nearly a century. In 1812 he published the results of measurements of the periods of pendulums and compared them with measurements from other parts of the world and came to the conclusion that the departure from predicted values was due to heterogeneity in the geology of the Earth.In 1814 he returned to France with his son Edouard. He was reinstated into the French army with the rank of Lieutenant-Colonel and was made Chevalier of St Louis.
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The gridiron pendulum consists of alternating parallel rods of two metals with different thermal expansion coefficients, such as steel and brass. The rods are connected by a frame in such a way that their different thermal expansions (or contractions) compensate for each other, so the overall length of the pendulum, and thus its period, stays constant with temperature. The gridiron pendulum was used during the Industrial Revolution period in regulator clocks, precision clocks employed as time standards in factories, laboratories, office buildings, and post offices to schedule work and set other clocks. The gridiron became so associated with quality timekeeping that to this day many clocks have pendulums with decorative fake gridirons, which have no temperature compensating qualities.
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Ivan Gough (born ) is an Australian house music producer and DJ. His first release, a remix of Pendulums "I Need You" became an instant club anthem, being played by the likes of Paul Oakenfold and Pete Tong in the United Kingdom. He released various tracks throughout the late 1990s and was an influential producer in the Melbourne underground scene working with "Zero Tolerance" recordings running their CBD studio. In 2004, he and fellow Melbourne DJ Grant Smillie began the production outfit TV RockZoe Badwi has a hit on her hands and toured with the Future Music Festival in 2010.Stafford Brothers, Ajax, Grant Smillie join Future Music Festival Gough left TV Rock early in 2013 to pursue solo projects.
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But shape also matters—even a piece of gold leaf (the heaviest of metals) floats through the air and a bladder filled with air falls much more slowly than lead. [128] Measuring the speed of a fall is difficult because of the small time intervals involved and his first way round this used pendulums of the same length but with lead or cork weights. The period of oscillation was the same, even when the cork was swung more widely to compensate for the fact that it soon stopped. [139] This leads to a discussion of the vibration of strings and he suggests that not only the length of the string is important for pitch but also the tension and the weight of the string.
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The time for one complete cycle, a left swing and a right swing, is called the period. The period depends on the length of the pendulum and also to a slight degree on the amplitude, the width of the pendulum's swing. From the first scientific investigations of the pendulum around 1602 by Galileo Galilei, the regular motion of pendulums was used for timekeeping, and was the world's most accurate timekeeping technology until the 1930s. The pendulum clock invented by Christian Huygens in 1658 became the world's standard timekeeper, used in homes and offices for 270 years, and achieved accuracy of about one second per year before it was superseded as a time standard by the quartz clock in the 1930s.
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Upon its release, "#GetItRight" received generally favorable reviews from music critics, who appreciated its overall production. Mariah Eakin from The A.V. Club complimented its placement on Bangerz, describing the song as "perfectly appropriate for an early-twentysomething, albeit one who has no problem with nudity." Nick Catucci of Entertainment Weekly opined that the track is "every bit as immodest as you'd expect from a young lady who recently spawned a craze for swinging unattired on public pendulums", and further commented that it "solved the riddle [of] what the grinning naked women in Robin Thicke's 'Blurred Lines' video were thinking". Writing for Slant Magazine, Kyle Fowler appreciated "#GetItRight" for being a "sexy slice of pop-funk whose lyrics boast a raunchy but refreshing display of female sexual agency".
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This consisted of a "grid" of parallel rods of high-thermal-expansion metal such as zinc or brass and low-thermal- expansion metal such as steel. If properly combined, the length change of the high-expansion rods compensated for the length change of the low-expansion rods, again achieving a constant period of the pendulum with temperature changes. This type of pendulum became so associated with quality that decorative "fake" gridirons are often seen on pendulum clocks, that have no actual temperature compensation function. Beginning around 1900, some of the highest precision scientific clocks had pendulums made of ultra-low-expansion materials such as the nickel steel alloy Invar or fused silica, which required very little compensation for the effects of temperature.
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The campus housed University of the Trees Press which published Christopher Hills' writings and the research of a number of resident students who obtained degrees at the university and wrote books on light & color frequencies and the science of Radionics. A small workshop produced pendulums for dowsing and a line of negative ion generators. With the buildup of the vitamin business surrounding discoveries that spirulina had significant weight loss benefits University of the Trees became one of the largest employers in the San Lorenzo Valley"From Counterculture to Mainstream" – Santa Cruz Sentinel (Cover), Aug 19, 1984 and leased more than 10 buildings in Boulder Creek for housing students and warehousing for Light Force,"Spirulina – Miracle Pill or Mind Pill? " – The Press Democrat, September 24, 1981, p.
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Pendulums inside the valve reacted to the deceleration profile of the vehicle and would partially close, reducing the pressure in the brake lines and moderating the deceleration so that the emergency stop was not dangerously abrupt. In operation the ACT systems had more in common with a metro system or the people movers used at airports, using relatively large cars with up to 20 passengers and making stops at all requested stations. As deployed, it was not a true personal rapid transit system, like the contemporary Cabinentaxi or the modern ULTra, which offer true point-to-point service for every car. ACT's unique feature was the embedded bypasses, which allowed bi-directional service on a line consisting primarily of a single track.
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The Memorial Chapel, in adobe and red tile architecture, also reflects early California's Spanish and Mexican lineage. Created by Benjamin Mako and his team of artists, the stained glass windows display California history from 1769 to 1909. Beyond the stained glass window there is a carved reredos leading toward the mural interpretation of The Ascension of Christ, created by R. Brownell McGrew. The Rotunda contains the statue of the mythological figure Danae; the statue hall features busts of Constantine the Great, Charlemagne, St. Augustine, Dante Alighieri, Desiderius Erasmus, William Tyndale, John Knox, John Milton, Thomas Jefferson and Ralph Waldo Emerson. There is also a “Paradise” mosaic, a rendition of Raphael's fresco, and a Foucault pendulum, one of eightList of Foucault pendulums in Southern California.
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Invar is used where high dimensional stability is required, such as precision instruments, clocks, seismic creep gauges, television shadow-mask frames, valves in engines and large aerostructure molds. One of its first applications was in watch balance wheels and pendulum rods for precision regulator clocks. At the time it was invented the pendulum clock was the world's most precise timekeeper, and the limit to timekeeping accuracy was due to thermal variations in length of clock pendulums. The Riefler regulator clock developed in 1898 by Clemens Riefler, the first clock to use an invar pendulum, had an accuracy of 10 milliseconds per day, and served as the primary time standard in naval observatories and for national time services until the 1930s.
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For simplicity, consider that 5% to be a 5 degree angle. Using simple trigonometry, 5 degrees at 20,000 feet is approximately 1,750 feet, an error that would place the bombs far outside their lethal radius. In tests, accuracies of 3 to 4 degrees were considered standard, and angles as high as 15 degrees were not uncommon. Given the seriousness of the problem, systems for automatic levelling of bombsights was a major area of study before World War II, especially in the US.All of the USAAC's pre-war bombsights featured some system for automatically levelling the sight; the Estopery D-series used pendulums, Sperry designs used gyroscopes to stabilize the entire sight, and the Norden used gyroscopes to stabilize the optics.
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The accuracy of the measured value of has increased only modestly since the original Cavendish experiment. is quite difficult to measure because gravity is much weaker than other fundamental forces, and an experimental apparatus cannot be separated from the gravitational influence of other bodies. Furthermore, gravity has no established relation to other fundamental forces, so it does not appear possible to calculate it indirectly from other constants that can be measured more accurately, as is done in some other areas of physics. Measurements with pendulums were made by Francesco Carlini (1821, ), Edward Sabine (1827, ), Carlo Ignazio Giulio (1841, ) and George Biddell Airy (1854, ). Cavendish's experiment was first repeated by Ferdinand Reich (1838, 1842, 1853), who found a value of ,F.
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Between 1859 and 1891, Peirce was intermittently employed in various scientific capacities by the United States Coast Survey and its successor, the United States Coast and Geodetic Survey,Burch, Robert (2001, 2010), "Charles Sanders Peirce", Stanford Encyclopedia of Philosophy where he enjoyed his highly influential father's protection until the latter's death in 1880. That employment exempted Peirce from having to take part in the American Civil War; it would have been very awkward for him to do so, as the Boston Brahmin Peirces sympathized with the Confederacy. At the Survey, he worked mainly in geodesy and gravimetry, refining the use of pendulums to determine small local variations in the Earth's gravity. He was elected a resident fellow of the American Academy of Arts and Sciences in January 1867.
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By a complicated method that was an early use of calculus, he showed this curve was a cycloid, rather than the circular arc of a pendulum,Huygens, Horologium Oscillatorium, Part 2, Proposition 25 confirming that the pendulum was not isochronous and Galileo's observation of isochronism was accurate only for small swings. Huygens also solved the problem of how to calculate the period of an arbitrarily shaped pendulum (called a compound pendulum), discovering the center of oscillation, and its interchangeability with the pivot point. gives a detailed description of Huygen's methods The existing clock movement, the verge escapement, made pendulums swing in very wide arcs of about 100°. Huygens showed this was a source of inaccuracy, causing the period to vary with amplitude changes caused by small unavoidable variations in the clock's drive force.
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Pendulums (unlike, for example, quartz crystals) have a low enough Q that the disturbance caused by the impulses to keep them moving is generally the limiting factor on their timekeeping accuracy. Therefore, the design of the escapement, the mechanism that provides these impulses, has a large effect on the accuracy of a clock pendulum. If the impulses given to the pendulum by the escapement each swing could be exactly identical, the response of the pendulum would be identical, and its period would be constant. However, this is not achievable; unavoidable random fluctuations in the force due to friction of the clock's pallets, lubrication variations, and changes in the torque provided by the clock's power source as it runs down, mean that the force of the impulse applied by the escapement varies.
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Galileo studied speed and velocity, gravity and free fall, the principle of relativity, inertia, projectile motion and also worked in applied science and technology, describing the properties of pendulums and "hydrostatic balances", inventing the thermoscope and various military compasses, and using the telescope for scientific observations of celestial objects. His contributions to observational astronomy include the telescopic confirmation of the phases of Venus, the observation of the four largest satellites of Jupiter, the observation of Saturn's rings, and the analysis of sunspots. Galileo's championing of heliocentrism and Copernicanism met with opposition from within the Catholic Church and from some astronomers. The matter was investigated by the Roman Inquisition in 1615, which concluded that heliocentrism was "foolish and absurd in philosophy, and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture".
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In the first case a mathematical formulation mirrors centrifugal force; in the second it creates it. Christiaan Huygens coined the term "centrifugal force" in his 1659 De Vi Centrifuga and wrote of it in his 1673 Horologium Oscillatorium on pendulums. In 1676–77, Isaac Newton combined Kepler's laws of planetary motion with Huygens' ideas and found > the proposition that by a centrifugal force reciprocally as the square of > the distance a planet must revolve in an ellipsis about the center of the > force placed in the lower umbilicus of the ellipsis, and with a radius drawn > to that center, describe areas proportional to the times. Newton coined the term "centripetal force" (vis centripeta) in his discussions of gravity in his De motu corporum in gyrum, a 1684 manuscript which he sent to Edmond Halley.
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Horologium oscillatorium sive de motu pendulorum, 1673 Illustration of Huygens' 1673 experimental pendulum clock from Horologium Oscillatorium. Huygens placed cycloidal-shaped metal "cheeks" on either side of the pendulum string, to force the pendulum to move in a cycloidal path, to increase accuracy. Horologium Oscillatorium: sive de motu pendulorum ad horologia aptato demonstrationes geometricae (Latin for "The Pendulum Clock: or geometrical demonstrations concerning the motion of pendula as applied to clocks") is a book published by Christiaan Huygens in 1673; it is his major work on pendulums and horology. This work is regarded as one of the three most important works done on mechanics in the 17th century, the other two being Galileo’s Discourses and Mathematical Demonstrations Relating to Two New Sciences (1638) and Isaac Newton’s Philosophiæ Naturalis Principia Mathematica (1687).
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The 18th- and 19th-century wave of horological innovation that followed the invention of the pendulum brought many improvements to pendulum clocks. The deadbeat escapement invented in 1675 by Richard Towneley and popularised by George Graham around 1715 in his precision "regulator" clocks gradually replaced the anchor escapement and is now used in most modern pendulum clocks. The observation that pendulum clocks slowed down in summer brought the realisation that thermal expansion and contraction of the pendulum rod with changes in temperature was a source of error. This was solved by the invention of temperature-compensated pendulums; the mercury pendulum by George Graham in 1721 and the gridiron pendulum by John Harrison in 1726. With these improvements, by the mid-18th century precision pendulum clocks achieved accuracies of a few seconds per week.
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An educated man and a patriot,Eugène Ritter, "Isaac Rousseau, le père de Jean-Jacques" , 1891 Isaac seems to have been very attached to his son and educated him himself until he was aged ten, though he became more distant in the years that followed. In 1722 he was almost imprisoned thanks to a quarrel and he went into exile from Geneva, leaving his son in the care of Isaac's brother-in-law Gabriel Bernard. Isaac settled in Nyon, slightly to the north-east of Geneva, and remarried. He then became one of the Genevan clockmakers who settled in the Ottoman Empire, where he was put in charge of regulating the pendulums in the Topkapi Palace – an important role, since these clocks regulated the exact time for Islamic prayers.
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" Molecular biologist Jennifer Doudna praised the book as a "fantastic adventure across time and space, grounded in science but deeply thought-provoking about human nature and the future of our species". J. Doudna, Books of the Year issue, WSJ Dec 12, 2015 Bill Gates recommended Seveneves as one of five books to read in the summer of 2016, praising in particular its scientific accuracy. He writes, "Seveneves reminded me of all the things I love about science fiction". The Guardians Steven Poole was more critical in his review, criticizing the work as being overly descriptive, and observing: "Once we arrive in the novel's snail-paced last third, there are lots and lots of lavish descriptions of imaginary machines: city-sized orbiting habitats, giant pendulums reaching down into the Earth's atmosphere, 'sky trains'.
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This equation gives rise to formidable quality factors. For a 4 m x 4 m ring equipped with 1 ppm mirrors (R = 1-10−6) we would get, at 474 THz, Q = 4×1013. This quality factor produces a passive resonance line of rms = 5 Hz, which is eight orders of magnitude smaller than the atomic linewidth of the Ne line (a 1:1 mixture of the two isotopes and has a gain bandwidth of about 2.2 GHz). (Note that for example in regular pendulums the Q is of the order of 103 and in wristwatch-type quartzes it is of the order of 106.) The active ring further reduces the linewidth by several orders of magnitude, and increasing the measuring time may additionally decrease the linewidth by many orders of magnitude.
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The movements of the pendulums has contributed to identify the free oscillations of the Earth, and to show that the secular term tilting of the cave is towards the northwest. The marine tides of the Adriatic have a loading effect in the cave, as have also the underground karstic floods of the river Timavo that disappears at the Škocjan Caves in Slovenia. The Grotta Gigante tiltmeters are the only existing instruments to have recorded four out of five greatest earthquakes in the recent 50 years, which are the earthquakes of Chile 1960 (the greatest earthquake ever instrumentally recorded) and Chile 2010 (the fifth in the scale of recorded worldwide mega-events) the tsunami-generating event of the Sumatra-Andaman islands of 2004 (third greatest event) and the event of Japan 2011 (fourth greatest event), allowing an absolute-amplitude comparison between these events.
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According to the format of the exam, a correct answer deserved a full credit. But issuing a full credit would have violated academic standards by rewarding a student who had not demonstrated competence in the academic field that had been tested (physics). Neither of two available options (pass or fail) was morally acceptable. Calandra asked the student the same question, and received a wealth of different answers including dropping the barometer from the top of the building and timing its fall with a stopwatch; trading the barometer to the building's superintendent in return for the information wanted; creating two small pendulums and measuring the variation of g from the ground to the top of the building; creating a pendulum as high as the building and measuring its period; and comparing the length of the shadows of the building and the barometer.
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The piece is truly spatial and visual, and the melodies one hears are simply the result of the routes drawn in the space by the composer. In Galileo (1999-2005), bells swing like pendulums in tempos determined by the length of their strings, permitting the composer to make music following the laws of the pendulum, as formulated by Galileo Galilei in the 17th century. Since 2000 the work of Johnson is less concerned with theatricality and turns more toward musical form and mathematics. From about 2004 to 2010 he worked with what he calls “rational harmonies” in pieces like 360 Chords for orchestra (2005) and Twelve (2008) for piano. In the following years one may observe, among other things, an increasing interest for rhythm, as in Vermont Rhythms (2008), Munich Rhythms (2010), Tick-Tock Rhythms (2013), and Dutch Rhythms (2018).
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He used freeswinging pendulums as timers in scientific experiments and for keeping time for music. In 1637, when he was 73, Galileo had the idea of a mechanism that would keep the pendulum swinging by giving it pushes, an escapement, thus allowing it to be applied to clocks. Since he was by then totally blind, he described the mechanism to his son Vincenzio, who drew a picture from his description. Galileo's student and biographer, Vincenzo Viviani, describes the invention > One day in 1641, while I was living with him at his villa in Arcetri, I > remember that the idea occurred to him that the pendulum could be adapted to > clocks with weights or springs, serving in place of the usual tempo, he > hoping that the very even and natural motions of the pendulum would correct > all the defects in the art of clocks.
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The Quéntar dam was inaugurated on May 11, 1976; is located in the hill of the Bermejales (by where it is acceded to the swamp), and the hill of Castillejo. Its wall has a height of something more than 100 meters and has a capacity of 13 million cubic meters. The quéntar swamp has the immediate purpose of complementing the water supply of the city of Granada and the irrigation of its meadow. With the Canales swamp, supplies a population of more than 300,000 and a butterfly valves and Howell-Bunger. The dam is monitored with a complete installation for the observation and recording of its deformations, temperature and tensional state, counting with pendulums, electroacoustic extensometers, air and water thermometers, tensiometric capsules, flexometers, cliometrics bases and a system of measurements of displacements by collimation in the coronation of the dam attend the demands of irrigation of about 10,000 hectares.
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Animation of anchor escapement Invented around 1657 by Robert Hooke, the anchor (see animation to the right) quickly superseded the verge to become the standard escapement used in pendulum clocks through the 19th century. Its advantage was that it reduced the wide pendulum swing angles of the verge to 3–6°, making the pendulum nearly isochronous, and allowing the use of longer, slower-moving pendulums, which used less energy. The anchor is responsible for the long narrow shape of most pendulum clocks, and for the development of the grandfather clock, the first anchor clock to be sold commercially, which was invented around 1680 by William Clement, who disputed credit for the escapement with Hooke. The escapement increased the accuracy of pendulum clocks to such a degree that the minute hand was added to the clock face in the late 1600s (before this, clocks had only an hour hand).
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Among his earliest demonstrations were discussions of the nature of air, the implosion of glass bubbles which had been sealed with comprehensive hot air, and demonstrating that the Pabulum vitae and flammae were one and the same. He also demonstrated that a dog could be kept alive with its thorax opened, provided air was pumped in and out of its lungs, and noting the difference between venous and arterial blood. There were also experiments on the subject of gravity, the falling of objects, the weighing of bodies and measuring of barometric pressure at different heights, and pendulums up to . Instruments were devised to measure a second of arc in the movement of the sun or other stars, to measure the strength of gunpowder, and in particular an engine to cut teeth for watches, much finer than could be managed by hand, an invention which was, by Hooke's death, in constant use.
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The measure of a harmonic oscillator's resistance to disturbances to its oscillation period is a dimensionless parameter called the Q factor equal to the resonant frequency divided by the resonance width. has an excellent comprehensive discussion of the controversy over the applicability of Q to the accuracy of pendulums. The higher the Q, the smaller the resonance width, and the more constant the frequency or period of the oscillator for a given disturbance. The reciprocal of the Q is roughly proportional to the limiting accuracy achievable by a harmonic oscillator as a time standard.Matthys, 2004, p.32, fig. 7.2 and text The Q is related to how long it takes for the oscillations of an oscillator to die out. The Q of a pendulum can be measured by counting the number of oscillations it takes for the amplitude of the pendulum's swing to decay to 1/e = 36.8% of its initial swing, and multiplying by 2π.
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In 1673 Dutch scientist Christiaan Huygens in his mathematical analysis of pendulums, Horologium Oscillatorium, showed that a real pendulum had the same period as a simple pendulum with a length equal to the distance between the pivot point and a point called the center of oscillation, which is located under the pendulum's center of gravity and depends on the mass distribution along the length of the pendulum. The problem was there was no way to find the location of the center of oscillation in a real pendulum accurately. It could theoretically be calculated from the shape of the pendulum if the metal parts had uniform density, but the metallurgical quality and mathematical abilities of the time didn't allow the calculation to be made accurately. To get around this problem, most early gravity researchers, such as Jean Picard (1669), Charles Marie de la Condamine (1735), and Jean-Charles de Borda (1792) approximated a simple pendulum by using a metal sphere suspended by a light wire.
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David Robertson (1875 – 1941) was the first Professor of Electrical Engineering at Bristol University. Robertson had wide interests and one of these was horology – he wanted to provide the foundation of what we could call “horological engineering”, that is, a firm science-based approach to the design of accurate mechanical clocks. He contributed a long series on the scientific foundations of precision clocks to the Horological Journal which was the main publication for the trade in the UK; he and his students undertook research on clocks and pendulums (some funded by the Society of Merchant Venturers); and he designed at least one notable clock, to keep University time and control the chiming of Great George in the Wills Memorial Building from its inauguration on 1925, for which he also designed the chiming mechanism. Today, we get accurate time from atomic clock ensembles in observatories round the world, compared and distributed by GPS satellites and over the internet, and displayed on almost any public or personal screen.
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Entrainment is a term originally derived from complex systems theory, and denotes the way that two or more independent, autonomous oscillators with differing rhythms or frequencies, when situated in a context and at a proximity where they can interact for long enough, influence each other mutually, to a degree dependent on coupling force, such that they adjust until both oscillate with the same frequency. Examples include the mechanical entrainment or cyclic synchronization of two electric clothes dryers placed in close proximity, and the biological entrainment evident in the synchronized illumination of fireflies. Entrainment is a concept first identified by the Dutch physicist Christiaan Huygens in 1665 who discovered the phenomenon during an experiment with pendulum clocks: He set them each in motion and found that when he returned the next day, the sway of their pendulums had all synchronized. Such entrainment occurs because small amounts of energy are transferred between the two systems when they are out of phase in such a way as to produce negative feedback.
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His first published papers, which appeared in 1842 and 1843, were on the steady motion of incompressible fluids and some cases of fluid motion. These were followed in 1845 by one on the friction of fluids in motion and the equilibrium and motion of elastic solids, and in 1850 by another on the effects of the internal friction of fluids on the motion of pendulums. To the theory of sound he made several contributions, including a discussion of the effect of wind on the intensity of sound and an explanation of how the intensity is influenced by the nature of the gas in which the sound is produced. These inquiries together put the science of fluid dynamics on a new footing, and provided a key not only to the explanation of many natural phenomena, such as the suspension of clouds in air, and the subsidence of ripples and waves in water, but also to the solution of practical problems, such as the flow of water in rivers and channels, and the skin resistance of ships.
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