[填空题]
A person of mass 75 kg stands )rw hphf3l +z1ctfs58at the center of a rota;2o8xtbz bj /-4 fy nej )ker9u:;-mkxk*ou wating merry-go-round platform of radi t/8j o xf9kbbu*k)k4-omz;xew -r euynj2;:aus 3.0 m and moment 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