[填空题]
A grinding wheel is a ubw. t.ri*hoj1niform cylinder with a radius of 8.50 cm apod2y/ ji2eguns 4z 54nd a mass of 0.580pzdgsy5j2n2o /ie u 44 kg. Calculate (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。 $m \cdot N$