A balloon starts riding from ground from rest with an upward acceleration 2 m/s^2. Just after 1 s, a stone is dropped from it. The time taken be stone to strike the ground is nearly1) 0.3 s2) 0.7 s3) 1 s4) 1.4 sWhy we didnt used the value of acceleration as 2 m/s^2 or 2+10 to calculate s?