# gyroscope

## Definitions

• WordNet 3.6
• n gyroscope rotating mechanism in the form of a universally mounted spinning wheel that offers resistance to turns in any direction
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Webster's Revised Unabridged Dictionary
• Gyroscope A form of the above apparatus, invented by M. Foucault, mounted so delicately as to render visible the rotation of the earth, through the tendency of the rotating wheel to preserve a constant plane of rotation, independently of the earth's motion.
• Gyroscope A rotating wheel, mounted in a ring or rings, for illustrating the dynamics of rotating bodies, the composition of rotations, etc. It was devised by Professor W. R. Johnson, in 1832, by whom it was called the rotascope.
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Century Dictionary and Cyclopedia
• n gyroscope An instrument consisting of a fly-wheel, the axis of which can turn freely in any direction, designed to illustrate the dynamics of rotating bodies. The instrument commonly called gyroscope is better named gyroscopic top (which see, under gyroscopic). The gyroscope proper of Foucault, shown in the figure, consists of a flywheel having the small conical bearings of its axis in a well-balanced metallic ring which carries two knife-edges in a line perpendicular to the axis of the fly-wheel; these knife-edges bear upon agates carried in a horizontal plane by an outer vertical ring half suspended from a small copper wire and turning about a vertical axis. The axis of the wheel can thus turn in any direction. By means of an accessory apparatus a velocity of 150 turns a second can be imparted to the fly-wheel. The principal experiments with this apparatus are as follows: First experiment.— If, when the fly-wheel is turning rapidly, no considerable force is applied to change the direction of its axis, its direction will remain almost unchanged. For, suppose it were proposed, by an instantaneous impulse, to turn this axis round a fixed axis perpendicular to it; then, at the point where this fixed axis cuts the rim of the fly-wheel, a particle would have to be deflected, and it can be shown by the parallelogram of motions that a velocity must be communicated to it proportional to the velocity it already possessed. Hence, the force required to rotate the axis of a fly-wheel increases with its velocity. Accordingly, when the velocity is very high, the friction on the bearings will change the direction of the axis but very little. But all the surrounding objects partake of the rotation of the earth upon its axis. Consequently, the axis of the fly-wheel will have a relative rotation; and this may be observed with a microscope. Second experiment.— If the fly-wheel was attached to its axis by a hinge, so that its plane was free to take any inclination to the axis, it is plain that by virtue of centrifugal force it would become perpendicular to the axis, since in this way its particles would be furthest from the axis. If then the outer ring of the gyroscope be held fast in such a position that the axis of the fly-wheel is free to move in the meridian plane, it partakes of the rotation of the earth; and the rotation of the earth and that of the fly-wheel being compounded, the axis of resultant rotation is not quite perpendicular to the fly-wheel. Accordingly, the inner ring will turn on its knife-edges until the axis of the fly-wheel is brought into parallelism with that of the earth, so that the wheel revolves from west to east like the earth. Third experiment.—On the same principle, if the outer ring be free to turn, but the inner one be fixed horizontally, the outer ring will turn so as to bring the axis of the fly-wheel into the meridian. Fourth experiment.—Let the inner wheel be thrown out of balance by hanging a weight upon it near one end of the axis; then this weight will each instant communicate a rotation about the knife-edges, compounding itself with the rotation of the fly-wheel about its axis as the rotation of the earth does in the third experiment, and a rotation of the outer ring round its vertical axis will result. Since the resultant axis of the first two rotations is very near that of the fly-wheel, the tendency of the weight to fall will be but slight, and under the influence of the centrifugal force of the third rotation it will move like a conical pendulum.
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Chambers's Twentieth Century Dictionary
• n Gyroscope jī′ro-skōp an instrument for the exhibition of various properties of rotation, and the composition of rotations
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## Etymology

Webster's Revised Unabridged Dictionary
Gr. gy^ros ring, circle + -scope,
Chambers's Twentieth Century Dictionary
Gr. gyros, a circle, skopein, to see.

## Usage

### In literature:

Then the gyroscopes took over.
"Hunters Out of Space" by Joseph Everidge Kelleam
Or you can navigate manually by using Gyroscopic Navigational if you want.
"A Fine Fix" by R. C. Noll
My head's spinning like a gyroscope.
"The Gay Rebellion" by Robert W. Chambers
The gyroscopic mechanism had broken from its fastenings and rolled forward.
"The Heads of Apex" by Francis Flagg
The gyroscopic principle was used.
"Lords of the Stratosphere" by Arthur J. Burks
In the center where the light was thickest, something like a gyroscope appeared to be revolving.
"Astounding Stories of Super-Science, May, 1930" by Various
The basis of the mechanical pilot is a gyroscope that controls pistons connected with the rudder and elevators of the plane.
"Astounding Stories of Super-Science, November, 1930" by Various
Its gyroscopic quality steadies it and the whirl of its propeller tends always to lift its weight.
"Old Plymouth Trails" by Winthrop Packard
The gyroscope, with which all torpedoes are equipped, caused the projectile to right itself.
"The Battleship Boys' First Step Upward" by Frank Gee Patchin
They even were able to keep sun-time and tell the seasons, by means of gyroscopes!
"Astounding Stories, August, 1931" by Various
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### In news:

Controlled by Sperry gyroscopes, a pilotless Curtiss B-2 flies over Sacramento, Calif, in May 1930.
With the tool's gyroscopic technology, users rotate their wrist one-quarter turn to the right for forward or left for reverse, rather than by engaging a trigger.
This plastic child's bowl uses the principle of a gyroscope to stay upright.
Stephen Robinson and Soichi Noguchi have been enjoying the view while re-powering one gyroscope and replacing another.
The orbiting telescope shut itself down on Saturday when one of the three remaining gyroscopes used to stabilize and point the observatory failed after 12 hours of erratic behavior.
The symbolic picture of a kite or a poor semblance of a gyroscope joins two triangles into a diamond-shaped figure.
Among the new features is a dual-core processor, a built-in gyroscope and front- and rear-facing cameras.
Black & Decker adds gyroscope to screwdriver.
Black & Decker adds gyroscope to screwdriver .
With the screwdriver 's gyroscopic technology, users only need to rotate their wrist one-quarter turn to the right for forward or left for reverse.
STMicroelectronics offers tiny 3- axis gyroscope delivering power, speed, and design-in advantages.
Local boy Daniel Kim is making news with his gyroscopically stabilized alt-car.
The Apple iPhone 4, like the Nintendo Wii, makes good fun of gyroscope technology — and it's the gyroscope suppliers who will be laughing all the way to the bank.
Apple iPhone 4 to Trigger Gyroscope Onslaught : iSuppli.
The Segway is a motorized transportation device which uses gyroscopes to remain upright.
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### In science:

Future and ongoing experiments, such as the Gravity Probe B Gyroscope Experiment, satellite tests of the Equivalence principle, and tests of gravity at short distance to look for extra spatial dimensions could constrain extensions of general relativity.
Was Einstein Right? Testing Relativity at the Centenary
J is the angular momentum of the Earth, and v, n and r are the velocity, direction, and distance of the gyroscope.
Was Einstein Right? Testing Relativity at the Centenary
The second line in each case is the corresponding value for a gyroscope in polar Earth orbit at about 650 km altitude (Gravity Probe B, Sec. 3.3).
Was Einstein Right? Testing Relativity at the Centenary
The latter, also known as gyroscopic precession , occurs in situations where there is an additional torque (such as that of a gyroscope) that pushes on the spin angular momentum vector, forcing it to wobble.
Chern-Simons Modified General Relativity
Another type of torque-induced precession is also affected by CS modiﬁed gravity, namely that experienced by a gyroscope.
Chern-Simons Modified General Relativity
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