A ball is dropped vertically from `a` height `d` above the ground . It hits the ground and bounces up vertically to a height ` (d)//(2). Neglecting subsequent motion and air resistance , its velocity `v` varies with the height `h` above the ground as

Options

A.
B.
C.
D.

Answer

A

Explanation

`O` to `A: v^(2)=2g(d-h)`
`v-y` graph: `y^(2)=2g(d-x)`
Parabola open, leftward velocity is in downward direction, hence -ve.
`B` to `C: v^(2)=gd-2 g h`
v-y graph: `y^(2)=g(d-2x)`
Parabola open leftward.
Velocity is in upward direction, hence +ve.