From a point on the ground at a distance of 2m from the fot of a verticle wal, a ball is thrown at an angle of `45^(@)` which just clears the top of the wall and then strikes the ground at distance of 4m from the foot of the wall on the other side. The height of the wall is

Options

A. `2/3`m
B. `3/4`m
C. `1/3`m
D. `4/3`m

Answer

D

Explanation

`R=u^2/g` or `6=u^2/g , y=x tan theta -(gx^2)/(2u^2 cos^2 theta)`
or `h=2 tan 45^@ - 4/(2 cos^2 45^@ )(1/6)=2-2/3 = 4/3` m