Precession of a bicycle wheel.

moment of inertia, torque

To show precession of a bicycle wheel when acted on by an applied torque.

Bicycle wheel and weighted shaft on special stand, weight, weight hanger

Use the sliding weight on the end of the shaft to adjust the wheel and shaft to be in horizontal equilibrium with the small 0.05 kg weight removed from the cord loop. Show that adding the 0.05 kg weight to the cord loop simply unbalances the system. Now spin the bicycle wheel and again add the 0.05 kg weight to the loop and precession will occur.

It is rather difficult at the initial stage to explain the nutation of the shaft as it precesses. If a temporary lashing with a thick rubber band or cord is made at the pivot so that movement of the shaft in a vertical plane is resisted then a simple rotation of the shaft will take place. As a next step, repetition of the experiment without the lashing will show nutation in the precession when this complete demonstration is required.

Useful Links: Nutation is defined by my good friends at Dictionary.com. Updated on: 06/13/13