[问答题]
A wheel of mass M has r xc 7,jh85bpsxs4z qzve3/q* 26d/lv-htyjp5 qli1f radius R. It is standing vertically on the floor, and we want to exert a horizontal force F at its ax v/26 hpqljfi 5dytl1-le so that it will climb a step against which it rests (Fig. 8–55). The step has height h, where h