A spinning ice skater will speed up if he brings his arms close to his body. Which of the following statements explains this phenomenon?
A. Circular motion is always uniform.
B. Angular momentum is always conserved.
C. Centripetal acceleration cannot change.
D. A centripetal force always points outward.

Question

A spinning ice skater will speed up if he brings his arms close to his body. Which of the following statements explains this phenomenon?
A. Circular motion is always uniform.
B. Angular momentum is always conserved.
C. Centripetal acceleration cannot change.
D. A centripetal force always points outward.

anonymous · Answer

@aboswell133

Alternative B. It's always conserved if the net external torque is zero.