[问答题]
A wheel of mass M ha0ra5e o*azp t:s radio c;5xrb ykf/4us R. It is standing vertically on the floor, and we want to exert a horizontal force F at its axle so that it will climb a step against which it rests (F5bf4xy o;/ kcrig. 8–55). The step has height h, where h