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…..

Q. 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 height h above the ground as:

figure

Ans: (a)

Sol: When ball is falling down from height d and reaches at height h , then velocity acquired by the ball is

v2= 2g(d-h)    —(i)

This is downward velocity and is taken as negative .

When h = d , v = 0

When h =0 , v2 = (2 g d)

Hence from eqn(i) , the variation of v & h is parabolic below h axis

Author: Rajesh Jha

QuantumStudy.com

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