[填空题]
(a) What is the angular momentum of a 2; ve;9/l gxj3uqw4qo z.8-kjk) ua57n92dm,w .mtbrwvx6n)td- qo g uniform cylindrical grinding wheel of radius 18 cm wv jn m-xn,md 5)wow6qr t7.dtu)k2 b9ahen rotating at 1500 rpm? $kg \cdot m^2$
(b) How much torque is required to stop it in 6.0 s? $m \cdot N$