[填空题]
A centrifuge rotor rotn lqwvl7n4eksk 8u+ 49ating at 1rltefnxs6in+9hiw.t0f p 6zo (4/ h y00,300 rpm is shut off and is eventually brought uniformly to rest by a fricti yo( 0ei+t nf 46/0 snlhrzi.pxwfth96onal 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