[填空题]
(a) What is the angular mo le2f0qx2gx, 1y(mf ttmenjx6- y;g*zqx3 wmeat9tum of a 2.8-kg uniform cylindrical grinding wheel of radius 18 cm when rotating at jam 3y9*x6 ewgx-t zq;1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$