When an ice skater twirling on the point of a skate draws her arms in she ends up whirling faster. This is because
A) rotational energy is conserved.
B) linear momentum is conserved.
C) angular momentum is conserved.
D) a net external torque acts on the skater.

Question

Quizplus · Accepted Answer

The conservation of angular momentum applies in this situation. When the skater draws her arms in, her moment of inertia decreases, causing her angular velocity to increase to conserve angular momentum. No net external torque acts on the skater, and linear momentum is not conserved in this rotational motion.

When an Ice Skater Twirling on the Point of a Skate