[填空题]
(a) What is the angular momean o/sqvf v tk8be11..0x73ddat bbygg7dt0f-t1 fas+ utk 3+ntum of a 2.8-kg uniform cylindrical grinding wheel of radius 18 cm when rotating 7kbyf3d00db1 f+ x s- atg37t u+agttdat 1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$