A balloon of mass 10 kg is raising up with an acceleration of `20 ms^(-2)`. If a mass of 4 kg is removed from the balloon its acceleration becomes ( take, `g=10ms^(-2)`)

Options

A. `40 ms^(-2)`
B. `20 ms^(-2)`
C. `30 ms^(-2)`
D. `12 ms^(-2)`

Answer

A

Explanation

(a) For the motion of balloon,
Let upward force is F, then F-mg=ma
`implies" " F-10xx10=10xx20`
`implies" " F-100=200 implies F=300N`
When 4 kg mass is removed then weight of balloon
`6xxx10=60N`
Which is also smaller than the upward force.
So, `F-60=6xxa`
where, a =new upward acceleration
`implies" "300-60=60a implies 240=6a`
`therefore" " a=(240)/(6)=40 ms^(-2)`