A cockroach of mass m lies on the rim of a uniform disk of mass 6.50 m that can rotate freely about its center like a merry-go-round. Initially the cockroach and disk rotate together with an angular velocity of 0.200 rad/s. Then the cockroach walks half way to the center of the disk.
(a) What then is the angular velocity of the cockroach-disk system?
(b) What is the ratio K/K0 of the new kinetic energy of the system to its initial kinetic energy?
(c) What accounts for the change in the kinetic energy? (Select all that apply.)