[填空题]
A person of mass 75 kg stands at the center ofnen3:b* 06m9+t;ueie hakge i q1wf s7 a roklc8x (e)cupb:zr (c,lx6 a:qh (gj*dtating merry-go-round platform of radius 3.0 m and momg )8((kjz* :aeh cbccl6(ru: qp,xx ldent of inertia 920 $kg \cdot m^2$ 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