[填空题]
A grinding wheel is a unift 15 f4usp76z;oyc zhwrka/m 586a:ge m4cudkorm cylindezrlbsmu 9it :812 fgn,r with a radius of 8.50 cm and a mass of 0.580 kg. Calculate t9s: 8nizubrfg,12 lm (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。 $m \cdot N$