Question

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?

Answer 1

MomentofINertia= 1/2 massdisk*r^2+massman*distanceheis

So figure the moment of inertia at each point he stands.

Conservation of angular momentum applies
originalmomentum=finalmomentum
Iorig*worig=Ifinal*wfinal