A balloon with mass `m` is descending down with an acceleration a `(where altg)` . How much mass should be removed from it so that it starts moving up with an acceleration a?

Options

A. `(ma)/(g+a)`
B. `(ma)/(g-a)`
C. `(2ma)/(g+a)`
D. `(2ma)/(g-a)`

Answer

C

Explanation

mg = B = ma
`rArr B = mg - ma " "…….(i)`
`B - (m - m_(0)) g = (m - m_(0))a `
`rArr B = (m - m_(0)) a +(m-m_(0))g" "…….(ii)`
From (i) and (ii)
`mg - ma = (m - m_(0))a + (m-m_(0))g`
`m_(0) = (2ma)/((g+a))`