[填空题]
A centrifuge rotor rotating at 10,38f1fsobknu 7. 00 r(mel : c.o0wmn*taw;7yl 5i bapm is shut off and is eventually brought ulcebw7;0 iao ya nlwmm( .5*:tniformly to rest by a frictional torque of 1.2 $m \cdot N$ If the mass of the rotor is 4.80 kg and it can be approximated as a solid cylinder of radius 0.0710 m, through how many revolutions will the rotor turn before coming to rest, $rev$ how long will it take? s