[填空题]
A centrifuge rotor rotatian uen( m*du6,nkn(m+gk kr l :jqua0/9y o;n4zg at 10,300 rpm is shut off and is eventually brought uniformly to rest by a frictionanlujmk nq;/ y+og0ar :4k( zk9l 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