Which term is described by the wheel principle with a heavily weighted rim spinning rapidly?

• A. Rigidity
• B. Rhodopsin
• C. Rigidity in space
• D. The principle that a wheel with a heavily weighted rim spinning rapidly will remain in a fixed position in the plane in which it is spinning.

Answer: (D)

The wheel principle described is gyroscopic behavior driven by angular momentum. When a wheel has a heavy rim and spins rapidly, it develops a large angular momentum; this makes the wheel resistant to changes in the direction of its spin axis. If there are no significant external torques, the axis tends to stay pointed in the same direction, so the plane of the wheel remains fixed in space. The statement about a heavily weighted rim spinning rapidly staying in a fixed position in its spinning plane is a direct way of expressing this gyroscopic stability. In other words, the rapid spin creates a strong angular momentum that preserves orientation, unless external torque acts on the wheel.