[填空题]
(a) What is the angular momentum of al1niqlkli* ijr 89 ( )f(9s6dt)sp sou 2ep, 6c/mdd-wf 5ach j9 e)kf3v.8-kg uniform cylindrical grinding wheel of radius 18 cm waec,- dc6/h fv wkej5p)dm3 9fhen rotating at 1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$