[填空题]
(a) What is the angular momentum of a figureaj( p6*mlwgt(m) ,gdc skater spinnm,hkj)*g;oms;o-wj/f9 y ehnmp)3x r6h9 uvfing at 3.5 $rev/s$ with arms in close to her body, assuming her to be a uniform cylinder with a height of 1.5 m, a radius of 15 cm, and a mass of 55 kg? $kg \cdot m^2$ (b) How much torque is required to slow her to a stop in 5.0 s, assuming she does not move her arms? $m \cdot N$