[填空题]
A centrifuge rotor rotating at 10,300 rpm is sh ocg hm9a9ds-;v wxc8b. yqbw vt.1;-uut off and is eventually br,dn xgm;ao61s ought uniformly to rest by a frictional to;1nomgd ,x sa6rque 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