You are sitting on a stool that can rotate friction-free about its vertical axis, holding a spinning bicycle wheel that rotates in a horizontal plane. When you flip the bicycle wheel (turn it over through 180^o), you will A) rotate in the same direction the bicycle wheel was originally rotating. B) stay still. C) rotate in the direction opposite to that of the bicycle wheel's original rotation.

Question

Quizplus · Accepted Answer

The angular momentum of the system (you and the wheel) is conserved. When you flip the wheel, its angular momentum changes sign. To conserve angular momentum, you must rotate in the opposite direction.

You Are Sitting on a Stool That Can Rotate Friction-Free