Question

A balloon starts from the ground and moves vertically upwards with an acceleration of 2 m/s×s ,a stone is released from the balloon . find the time by the stone to reach the ground

Answer 1

Dear student,the given question is incomplete.so i add time as 1s.the question is
A balloon starts rising from ground from rest with an upward acceleration 2m/s^2 . Just after 1 second a stone is dropped from it. The time taken by the stone to strike the ground

Answer is
for balloon,
initial velocity of balloon=0 so,u=o
a=2m/s2
t=1s
v=u+at
v=2m/s (as u=0m/s ,a=2m/s2,t=1s)
s=ut+1/2at2
s=1m (as u=0m/s ,a=2m/s2,t=1s)
for stone,
u=-2m/s ,s=1m,a=9.8m/s2
at2+2ut-2s=0
9.8t2-4t-2=0
t=.7s