Question

If the air of weight $w$ is filled in an empty balloon which weighs $w_{1}$, the weight of the balloon will become $w_{2}$. Suppose the density of the air inside and outside the balloon is same, then

• 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 1

Answer: (C)

The apparent weight of the balloon $=w_{2}$
Apparent weight = real weight - upthrust
$\therefore w_{2}=$ real weight $-w$
But Real weight $=w_{1}+w$
$w_{2}=w_{1}+w-w=w_{1} $
$w_{2}=w_{1}$