A playground merry-go-round (uniform disk with mass M=150kg and radius R=2m) rotates on a frictionless axle through its center. A child of mass m=50kg is riding on the merry-go-round at a distance R=2m from the center, and the system is initially turning with angular velocity w=3.0 rads-1.
A) What is the kinetic energy of the child-merry-go-round-system? (The child is a point mass and Idisk=.5MR^2)
B) What is the final moment of inertia if the child moves to the center?
C) What is the angular velocity when the child is at the center?
D) As the child moves toward the center, does the kinetic energy of the system increase, decrease, or stay the same?