a cockroach of mass m lies on the rim of a uniform disk of mass 10m that can rotate freely about its center like a merry go round. Initially the cockroach and disk rotate together with an angular velocity of [tex] \omega_0[/tex]. Then the cockroach walks halfway to the center of the disk. What is the change in \Delta \omega[/tex] in the angular velocity of the system? I have no clue where to start...and no there are no numbers given. Can some one help me/give me a hint?