An empty balloon weighs `W`. If air equal in weight to `W` is pumped into the balloon, the weight of the balloon becomes `W_(2)`. Suppose that the density of air inside and outside the balloon is the same. Then

Options

A. `W_(2)=W_(1)+W`
B. `W_(2)=sqrt(W_(1)W)`
C. `W_(2)=W_(1)`
D. `W_(2)=W_(1)-W`

Answer

C

Explanation

Apparent weight of the balloon `= W_(2)`
Apparent weigt `=` real weight `-` upthrust
or `W_(2)=` real weight `=W_(1)+W`
`:. W_(2)=W_(1)+W-W=W_(1)`