[填空题]
A person of mass 75 kg st9tj1/ emqs(5n5r yuw zr2c89vfrpl/-lrf0 e;izyp :p:hnm0 t ands at the center of a rotating merry-go-round platform of radius 3.0 m and moment of inemrrpnz2e p0:lf89 vl fh- c; t0y/:prirtia 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