[填空题]
(a) What is the angular momentum of a 2.8-kg uniform cylindrical grindi.nxist6 4w fd5n *yqlwhcn3 rt:/gj5qzb9 a6b4 g wheel of radius 18 cm when rotating at 1500 rpm?g*/lqa :z j r3h9ync6qb45bwt $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$