Question

A body is dropped from a hot air balloon which is ascending with constant speed of
4m/s. At the time of drop the balloon was at the height 80m from the ground. Find (i)
the time it took to reach ground (ii) the speed with which it hit the ground.

Answer 1

assume that you throw a stone with veloity 4m/s from ground how much height will it take ?

it will be in air for 0.8 sec 0.4 for upflight and 0.4 for downflight

for that time 0.4 it will cover distance of 1/2*g*t^2=2metre for g = 10m/s^2

so now you just have to put 82 as height pf downfall so it ll be time of flight =$\sqrt{2h/g}$ it will be your answer similarly apply this for speed that is v^2=2 as put values