posted by jeff .
A children's merry-go-round in a park consists of a uniform 200kg disk rotating about a vertical axis. the radius of the disk is 6 m and a 100kg man is standing on the outer edge when the disk is rotating at a speed of 0.20rev/s. how fast will the disk be rotating if the man walks 3m in toward the center along a radial line?
MomentofINertia= 1/2 massdisk*r^2+massman*distanceheis
So figure the moment of inertia at each point he stands.
Conservation of angular momentum applies