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Question
A ball is thrown vertically upwards. It goes to a height 20 m and then returns to the ground. Taking acceleration due to gravity g to be 10 ms-2 , find :
the total time of journey of the ball .
Solution
Given, maximum height reached, s = 20 m
Acceleration due to gravity, g = 10 m/s2
Now total time for which the ball remains in air, t = 2u/g.
Or, t = 2 (20)/(10).
Or, t = 4s.
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