a small block is shot into a circular track.Each track rises to the same height.

What is the consition for which the normal reaction at th heighest point to be maximum.

joyfrancis i am unable to get a clear physical picture of your problem. Are there more than one tracks? What is the role of other tracks etc.? If possible please give the figure of problem 

ok i know the question! it has come in iit jee ,don't remember the year.

 

ans: the figure in which the topmost point has min curvature

 

soln:

 

Mg+N=mv²/R

 

N=mv²/R-Mg

 

so in all 4 options the curve which has mim. curvature at the topmost point offers the max. normal reaction.