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A body falls freely from a height of 125m (g = 10 m//s^2) after 2 sec gravity ceases to act Find the time taken by it to reach the ground? |
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Answer» Solution :Distance covered in 2s under gravity `s_(1)=1/2 gt^(2)=1/2 (10) (2^(2))=20m` velocity at the end of 2s, V=gt =(10)2=20m/s. Now at this instant gravity ceases to act a velocity by here after becomes constant The remaining distance which is 125-20=105 m is covered by the body with constant velocity of 20 m/s. Time taken to cover 105 m with constant velocity is given by `t_1=S/V RARR t_(1)=(105)/(20)=5.25s` Henee total time taken to reach the ground =2+5.25 =7.25s |
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