[填空题]
A centrifuge rotor rotating at 10,300 s7.e:iizv s7.yf p -jhrpm y oh hg5..ntjb 3ow.d3is shut off and is eventually brought unifohon5hw d3.tgb3 oyj..rmly 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