[填空题]
A person of mass 75 +h1+r16vkkvknm ( ciokg stands at the center 6v+ 7e5 fzofeopy6vaj2: o1rirs v)d.of a rotating merry-go-round platform of radius 3.0 m and moment of inertia pi6fdzfo6 5 :osyj2e 1)o vr+a.rev7 v920 $kg \cdot m^2$ The platform rotates without friction with angular velocity 2 $rad/s$ The person walks radially to the edge of the platform. (a) Calculate the angular velocity when the person reaches the edge. $rad/s$ (b) Calculate the rotational kinetic energy of the system of platform plus person before and after the person’s walk.$KE_i$ = J $KE_f$ = J