Answer
The angular velocity of the system decreases.
The rotational kinetic energy decreases.
The angular momentum of the system remains constant.
Work Step by Step
Since the rotational inertia of the system increases, the angular velocity of the system must decrease by the same factor.
Since work was done by the system to increase the child's angular velocity, the system loses energy. Therefore, the rotational kinetic energy decreases.
Since the rotational inertia of the system increases by the same factor that the angular velocity decreases, the angular momentum of the system remains constant.
