[填空题]
A person of mass 75 kg stan a,r5-r g3byed0ov/r hds at the center of a rotating merrm+l)eeo/wyhq 1n,,qhjk 0g :xy-go-round platform oghq/y,) j eh,:1ewxlk0+ mnoqf radius 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