A small block is shot into each of the four tracks as shown below. Each of the tracks rises to the same height. The speed with which the block enters the track is the same in all cases. At the highest point of the track, the normal reaction is maximum in

Options

A.
B.
C.
D.

Answer

A

Explanation

From conservation of energy , speed of the block at highest point will be same in all four cases . Say it is `v_0`.Equation of motion will be

`N +mg=(mv_0^2)/(R)rArrN=(mv_0^2)/(R)-mg`
R (the radius of curvature ) in first case is minimum . Therfore, normal reaction N will be maxmum in first case.