[填空题]
A grinding wheel is a uniform cylinder w qhrf k,1s nabdni.5/./l0h tbith a radius of 9n *penat 8dndqxd01(. c y7pt8.50 cm and a mass of 0.580 kg. Caeancp.tyd n*d (9017 txn8dqp lculate (a) its moment of inertia about its center, $\approx$ $kg \cdot m^2$ (b) the applied torque needed to accelerate it from rest to 1500 rpm in 5.00 s if it is known to slow down from 1500 rpm to rest in 55.0 s。 $m \cdot N$