A body falls freely from a height of 125m(g=10m//s^(2)) after 2 sec gravity ceases to act Find the time taken by it to reach the ground?

A body falls freely from a height of 125m(g=10m//s^(2)) after 2 sec gr

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