[问答题]
A wheel of mass M has rad yoomrb,sx8n 8-au; ,sius R. It is st6 ysrte/4,(uo x,mwbgt+ 4fjz a) -zfbanding vertically on the floor, and we want to exert a horizontal force F at its axle so that it will climb a step ajgx4o t stfw6,y b )z+4a,z(u/rf-be mgainst which it rests (Fig. 8–55). The step has height h, where h
Post time 2025-2-18 20:00:22
