A balloon of mass M is descending at a constant acceleration α. When a mass m is released from the balloon, it starts rising with the same acceleration α. Assuming that its volume does not change, what is the value of m?
Suppose F = upthrust due to buoyancy
Then while descending, we find Mg - F = Mα..............................(i)
When ascending, we have F - (M - m)g = (M - m) α ....................(ii)
Solving Eqs. (i) and (ii), we get m=[2αα+g]M