[填空题]
A grinding wheel is a vd;1e /dme.gx7mq. jqf (k6cluniform cylinder with a rakd130l0yb(mw, ew *)rql lhwydius of 8.50 cm and a mass of 0.580 kg. Chy0ylmwb e)wrkd1*ql ,w (3l0alculate (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。 $m \cdot N$