JEE Mains Model Paper 12

The horizontal velocity of the ball remains constant.
∴ the time of flight from C to F is twice the time of flight from A to C.
For the vertical motion from A to C, time t = √

2h

g

The vertical component of velocity before impact at C, v = √2gh
The vertical upward component of velocity after impact at C = ev
For the vertical motion from C to F
-h = ev (2t) +

1

2

(-g) (2t)2
⇒ -h = 2e (√2gh) (√

2h

g

) - 2g (√

2h

g

)2
⇒ e =

3

4