This seems pretty basic but I am drawing a blank. Thanks in advance. "A cat is sitting on the rim of a wooden turntable that is free to turn about a vertical axis. The turntable's mass is 3 times the cat's mass and is initially at rest. The cat then starts walking around the rim at a speed of 0.6m/s relative to the ground. How fast does the turntable's rim move relative to the ground?"