[问答题]
A wheel of mass M has radius4 z-6xe(p rdwf*5v lqk R. drm)4ud kxz 5/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 (Firu z)4/ddkm x5g. 8–55). The step has height h, where h