Problem
A person of mass 72 kg stands at the center of a rotating merry-go-round platform of radius 3.1 mm and moment of inertia 810 kg⋅m2. The platform rotates without friction with angular velocity 0.85 rad/s. The person walks radially to the edge of the platform.
1. Calculate the angular velocity when the person reaches the edge.
2. Calculate the rotational kinetic energy of the system of platform plus person before and after the person's walk.