[填空题]
A grinding wheel is a uniform cylinder wepq wt+5trauy:9 lq-r-( 3yt yith a ra k4.xi2j oxy6o7rkn7xdius of 8.50 cm and a mass of 0.580 kg. Calcul.yrjx k7no6x2ix47ko ate (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。 $m \cdot N$