6. Precession
• Precession is a change in the orientation of the rotational axis of
a rotating body. In other words, if the axis of rotation of a body is
itself rotating about a second axis, that body is said to be precessing
about the second axis. In physics, there are two types of
precession: torque-free and torque-induced.
7. Type of precession
• Torque-free precession implies that no external moment (torque) is
applied to the body. In torque-free precession, the angular
momentum is a constant, but the angular velocity vector changes
orientation with time.
• Torque-induced precession (gyroscopic precession) is the
phenomenon in which the axis of a spinning object (e.g., a gyroscope)
describes a cone in space when an external torque is applied to it.
8. GYROSCOPE
A gyroscope is a device used for measuring or
maintaining orientation and angular velocity. It is a spinning wheel or disc in
which the axis of rotation (spin axis) is free to assume any orientation by itself.
When rotating, the orientation of this axis is unaffected by tilting or rotation
of the mounting, according to the conservation of angular momentum.
