n=3拉力F=100N，动滑轮中G2=60N，物体上升速度v1=0.1m/snF=G1+G2物体重G1=nF-G2=3*100-60=240N自由端速度v2=nv1=3*0.1=0.3m/s拉力功率P2 = Fv2 = 100*0.3 = 30W拉力对G的功率P1 = GV1 = 240 * 0.1 = 24W
