[填空题]
(a) What is the angular m ,md/ x f53tx:tkvd/40v ulgzqomentum ofw cjr 40t+lw7w (yf(ybh :b0tx a 2.8-kg uniform cylindrical grinding wheel of radius( b+h0wyl4x(ft rtj:07cw bwy 18 cm when rotating at 1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$