[填空题]
A grinding wheel is a uniform cylinder with a radius of 8.50+cmm,eose7+s.w wm z* cf,3 od6ddh+0 0ojujaem and a mass of 0.58dj6d+o fu0hj3d,0 eoa0 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。 $m \cdot N$