[填空题]
(a) What is the angular momentum of a 2.8-kg uniforn:hh7ukq96 g 9hvywo,30vg ha m cyl ( bwb8wscfirt,. a,5gindrical grinding wheel of radius 18 cm 5sgi (t. frw ,c,abbw8when rotating at 1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$