A balloon carring some sand is moving down with a constant acceleration `a_(0)`. How much mass of sand should be removed, so that the balloon move up with same acceleration?

Explanation

`Mg-F_(B)=Ma_(0)` (i)
`F_(B):` upthrust
Let the mass removed be `m`.

`F_(B)-(M-m)g=(M-m)a_(0)` (ii)
Adding (i) and (ii), we get `m=(2Ma_(0))/(a_(0)+g)`