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Therefore, in spite of our efforts to turn the axis of rotating
bicycle wheel in plane YOZ ,this axis turns in perpendicular plane (fig
6.17).Such phenomenon is called gyroscopic effect.
In common case gyroscope is a device for measuring or

maintaining orientation based on the principles of angular momentum.
In essence, a mechanical gyroscope is a spinning wheel or disk whose
axis is free to take any orientation. Although this orientation does not

remain fixed, it changes in response to an external torque much less and
in a different direction than it would without the large angular
momentum associated with the disk's high rate of spin and moment of
inertia. Since external torque is minimized by mounting the device in

gimbals, its orientation remains nearly fixed, regardless of any motion of
the platform on which it is mounted.
Gyroscopes based on other operating principles also exist, such as

the electronic, microchip-packaged MEMS gyroscope devices found in
consumer electronic devices, solid-state
ring lasers, fibre optic gyroscopes, and

extremely sensitive quantum gyroscope.
Applications of gyroscopes include
inertial navigation systems, where

magnetic compasses would not work (as
in the Hubble telescope) or would not be
Figure 6.18 precise enough (as in ICBMs), or for the
stabilization of flying vehicles like radio-

controlled helicopters or unmanned aerial vehicles. Due to their
precision, gyroscopes are also used to maintain direction in tunnel
mining.

In the gyroscopic compass this gyro element is mounted in such a way
that no significant torques are applied. Under these circumstances the
moment of impulse remains constant. The axis of the gyro element always
points in the same direction, regardless of the maneuvers of the aircraft or

ship in which the gyro is mounted.
Ggyroscopic precession is the phenomenon in which the axis of a
spinning object "wobbles" when a torque is applied to it. For example,

consider a well known At the beginning humming-top rotates with
angular velocity  only around perpendicular axis as shown in fig.6.19

where L is angular momentum of this body.
And now push this rotating humming-top. But it will not fаll down
.Нumming-top keeps revolving with angular velocity  and at the

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