[填空题]
A centrifuge rotor rosi )5hq47umjk r l1o7otatikoee:rihu/ 06ng at 10,300 rpm is shut off and is eventually brought unifo6eh i/:ke 0orurmly 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