A figure skater is spinning on ice with their arms extended. When they pull in their arms, what happens to their angular velocity? Assume friction and drag are negligible.
A) Increases
B) Decreases
C) Stays the same
D) Can't tell, not enough information
Solution: There are no external torques, so angular momentum must remain constant. Since the moment of inertia decreases, angular velocity must increase to keep the product constant.