[填空题]
(a) What is the angular momentumt1k6u 1wm fu(n*j1 syo:vk *qr of a 2.8-kg unifons.6vba eb7ej8) eck 2rm cylindrical grinding wheel of radius 18 cm when 8eec 276ekjb sna)vb.rotating at 1500 rpm? $kg \cdot m^2$ (b) How much torque is required to stop it in 6.0 s? $m \cdot N$