[填空题]
(a) What is the angu(gvkl - 15f,rum m1uyz+w/ 9llxq0oam1z-6 5q0ck gm/wmzhlflar momentum of a 2.8-kg uniform cylindrical grinding wheel of radius 18 cm when rotating at 1500 rw1mzgz q6fl0m-k h/ c5pm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$