Question

A body is dropped from height of 120 m .after 2 sec gravity disappears . find total time taken by body to reach the ground.

Answer 1

s= 1/2*g*t²

s=1/2*10*2²

s=20 m

v= gt

v = 10×2

v= 20 m/s

when gravity disappears , the velocity is constant for the rest of 100 m.

v= s/t

20= 100/t

t= 100/20

t= 5 sec.

Total time = 5+2= 7 sec.