Question

A tennis ball is released from a height h and after freely falling on a wooden floor it rebounds and reaches height h/2. The velocity versus height of the ball during its motion may be represented graphically by 

(graph are drawn schematically and on not to scale)

Answer 1

Answer is (2) 

Velocity at ground (means zero height) is non-zero therefore one is incorrect and velocity versus height is non-linear therefore two is also incorrect.

Here we can see slope is very high when velocity is low therefore at maximum height the slope should be very large which is in option 2 and as velocity  increases slope must decrease therefor option 2 is correct.