[问答题]
A wheel of mass M has radius R. It is standing ve )gw66yku u4fvqg/ ug6rticalajg 8g62bflphbj.2;4 to.lsr ly on the floor, and we want to exert a horizontal force F at its a6bgjl .sofgaj8.t 2bp24r h;l xle so that it will climb a step against which it rests (Fig. 8–55). The step has height h, where h