[问答题]
A wheel of mass M has radius R. It is standing vertically on the floor, an xmoe8x-k5k. :e m:foid w x wkap8o3m56ie want to exert a horizontal fo8a6i k35wom pxrce 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
