# A ball falls under gravity from a height of 10 m with an initial downward velocity  It collides with theground, loses 50%of its energy in collision and then rises back to the same height. Find (i) the initial velocity  and (ii) the height to which the ball would rise after collision if the initial velocity was directed upwards instead of downwards? a) b) c) d)

## Question ID - 100230 | SaraNextGen Top Answer A ball falls under gravity from a height of 10 m with an initial downward velocity  It collides with theground, loses 50%of its energy in collision and then rises back to the same height. Find (i) the initial velocity  and (ii) the height to which the ball would rise after collision if the initial velocity was directed upwards instead of downwards? a) b) c) d)

Answer Key / Explanation : (b) -

(b)

TE at initial point

After collision,remaining energy

Hence,

(since after collision,it rebounds to same height )

m/s

The ball would rise to the same height after collision if the initial velocity was directed upwards instead of downwards. Since while returning to the same point, the body would possess the same velocity in the downwarddirection, hence  =10 m