Question

A ball is dropped vertically from a height d above the ground. If 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

• A.
• B.
• C.
• D.

Answer 1

Answer: (A)

Answer 2

As the ball falls, at height h the velocity of the ball is zero and at any height h,

v² = u²+2g(d−h), with decreasing h, v increases.

When h = 0, velocity v is maximum.

After the ball collides the floor, its velocity changes in magnitude as wall as direction, as the body goes to a smaller height in bouncing up. The change in velocity takes place within zero height and with no change in time.

Hence, (1) is correct.