[填空题]
(a) What is the angulatg;yzm;o u-m7 sqvk p- c-qi8*: ,n vsv23umma) ) xybbk+c*zbr momentum of a 2.8-kg uniform cylindrical grinding wheel of rabvc )*uakxm bby),:n v2+zsm3dius 18 cm when rotating at 1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$