Setup and Procedure
- An old bike wheel with counter weight is suspend by a chain from a swivel bearing in the ceiling.
- To use a different bike wheel, unclip the old blue one and clip the chain to the handle of the other wheel.
- Using one hand, grab the opposite handle, and position the wheel so that its rotational plane is vertical.
- Using your other free hand, grab the tire, give it a good pull back to start it spinning.
- You can now let the wheel go freely, but still hold onto the chain.
- It will remain upright as it spins.
Cautions, Warnings, or Safety Concerns
- Long hair, jewelry, and fingers can get caught in the spokes of the wheel especially when it’s rotating. Be sure to exercise caution.
Discussion
Once the wheel is spinning, it has angular momentum. The amount can be increased by making the wheel spin faster. Since angular momentum is conserved, the rotational axis of the wheel will remain in place. This would be the case if there were not any torques acting on the wheel. In our case, this net torque is due to the tension of the cable. The resultant effect is that our wheel precesses around the cable.