A person of mass 71 kilogram stands at the center of a rotating merry-go-round platform of radius 2.7 meter and moment of inertia 820kg•m2. The platform rotates without friction with angular velocity 0.85 rad/s. The person walks radically to the edge of the platform.
1. Obtain the angular velocity when the person reaches edge.
2. Obtain the rotational kinetic energy of the system of platform plus person before and after the person's walk.