A Child Standing on the Edge of a Freely Spinning

Multiple Choice

A child standing on the edge of a freely spinning merry-go-round moves quickly to the center. Which one of the following statements is necessarily true concerning this event and why?

A) The angular speed of the system decreases because the moment of inertia of the system has increased.
B) The angular speed of the system increases because the moment of inertia of the system has increased.
C) The angular speed of the system decreases because the moment of inertia of the system has decreased.
D) The angular speed of the system increases because the moment of inertia of the system has decreased.
E) The angular speed of the system remains the same because the net torque on the merry-go-round is zero N . m.