[填空题]
(a) What is the angud5p6f984sx+ w qjdvti:fu0l kn9vsp 4+j+q(dy hbj6s lar momentum of a 2.8-kg uniform cylindrical grinding wheel of radius 18 cm when rotasbnhy+64+ (qj jd spv9ting at 1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$