[填空题]
A block of mass m slides wite,cnz.s 1a)c/0a80 :y*qsohd ixb i+l)ns ekfhout friction alon/y :,+gv,; iu *bg9bigbfm7vv ,sjjhlg the looped track shown in Fig. 6–39. If the block is to remain on the track, even at the top of the circle (whose radius is :g*by, gbsv;l/v+ujh9m, f ij, ib 7vgr), from what minimum height h must it be released? r
