[填空题]
The block of mass m shk)-*kpx9 )c+:v ibjje)tgqi6*f m j p29wmnn3 sll8s liding without friction along the looped track shown in Fig. 6–39 is to remain on the track at all times, even at the very top of the loop of ra8s3 lwn2l9s mndius r.
(a) In terms of the given quantities, determine the minimum release height h (as in Problem 40). Next, if the actual release height is 2h, calculate r
(b) the normal force exerted by the track at the bottom of the loop, mg
(c) the normal force exerted by the track at the top of the loop, mg
(d) the normal force exerted by the track after the block exits the loop onto the flat section. mg
