[问答题]
A wheel of mass M has rad:),k;moyd k/aj z83g+jcdet rius R. It is standingb *:8x iyl xxt+6o4oqy*)w pse vertically on the floor, and we want to exert a horizontal force*8etoyxpb6l4 is+*x)w:xoyq F at its axle so that it will 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
