[问答题]
A wheel of mass M has ra2xzgl l ,d8y/bdius R. It is standing vertically on the floor, and6w +p bbt6*jcd we want to exert a horizontal force F at its axle so that it will+bjdbw6tp 6c* climb a step against which it rests (Fig. 8–55). The step has height h, where h
Post time 2025-2-18 20:00:22
