A ball is thrown vertically upwards with a velocity u. Calculate thevelocity with which it falls to the earth again.

Given:

u = Initial velocity


Ball is thrown up


Ball goes up and attains a maximum height H and then again comes down.



Let


u = Initial Speed


v = Final Speed


t = time


a = acceleration


s = distance


Case – I


Ball is going upward


a = -g


u = u


v = 0


s = H


Since,



H = …..1


Case – II


Ball comes downward


So, u = 0


v = Final Speed


a = g


Since,



H = …..2


From equations 1 and 2, we see that,


v = u


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