Question

A body is dropped from a balloon which is moving upward with a speed if 10m/s
.the body is dropped when the balloon is at a height of 390m from the surface of earth .Find the approximate time taken to reach the surface of earth .Take g=10m/s2

Answer 1

2gh=v^2-u^2
2×10×390=0^2-u^2
u=-10√78m/s

g=(v-u)/t
10=-10√78÷t
t=√78s
t=8.8s(approx.)