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

Answer

B

Explanation

`t_(1)+t_(2)=2v(sin45^(@))/g`
`d/(v cos 45^(@))+d/(ev cos 45^(@))=(2v sin45^(@))/grArr e=(gd)/(v^(2)-gd)`