A girl throws a ball with an initial velocity v at an angle `45^@`. The ball strikes a smooth vertical wall at a horizontal distance d from the girl and after rebound returns to her hands. What is the coefficient of restitution between wall and ball ? `(v^2 gt dg)`

Options

A. `v^(2) -gd)`
B. `(gd)/(v^(2)-gd)`
C. `(gd)/v^(2)`
D. `v^(2)/(gd)`

Answer

B

Explanation

`T = (d)/(v/sqrt(2)) + (d)/(ev//sqrt(2)) = (1+1/e)sqrt(d)/v)`
or `(2v//sqrt(2))/g = (1+1/e)(sqrt(2d)/v)`
or `e = (gd)/(v^(2)-gd)`