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

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)`