[填空题]
(a) What is the angular momentum of a 2.8-kg uniform cylindrical grinding 0ehi) rh.(-8 hs va,c rk:mtiehm1awqko*u/v+gl0qo 3trcn,d 9i4 k0 wheel of radius 18 cm wv,09m+ ck ton0 qd3i1owa q/g*ruh 4klhen rotating at 1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$