A demonstration gyroscope consists of a uniform disk with a 40.0-cm radius, mounted at the midpoint of a light 60.0-cm axle. The axle is supported at one end while in a horizontal position. How fast is the gyroscope precessing, in units of rad/s, if the disk is spinning around the axle at 30.0 rev/s?

THINK:
Determine the precessional angular speed of the gyroscope, in units of rad/s.
SKETCH:
The figure shows the precessional motion of a demonstration gyroscope.
RESEARCH:
The expression for the precessional angular speed
is given by

The moment of inertia of the disk of mass
and radius
is given by

SIMPLIFY:
From the diagram, 
The angular speed of precession of the gyroscope is given by

GIVEN DATA:
Radius of the uniform disk, 

The angular speed of the disk, 

Length of the axle, 

Acceleration due to gravity, 
CALCULATE:
The precessional angular speed of the gyroscope is given by