[填空题]
A grinding wheel is a uniform cylinder with a radius of 8.50 cm and a mass r pbv-/rd:j2bof f8c85 j 54k xlk od jys/d0irwmoy9l;.0.580 kg. Calcum0f 4jsi rkyx8dld59l/ c5woyko.8;j late (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。 $m \cdot N$