Question

The weight of an empty balloon on a spring balance is $W_1$. The weight becomes $W_2$ when the balloon is filled with air. Let the weight of the air itself be $\omega$. Neglect the thickness of balloon when it is filled with air. Also neglect the difference in the densities of the air inside and outside the balloon.

• A. $W_2=W_1$
• B. $W_2=W_1+\omega$
• C. $W_2<W_1+\omega$
• D. $W_2>W_1$

Answer 1

The correct option is C $W_2<W_1+\omega$

Here,the weight of the empty balloon is W1 and weight of the air which is being pumped into the balloon is W. This relation can be written as- W1+W

After filling the air , the weight becomes W2. If we neglect the difference in the densities of the air inside and outside the balloon , which is the mass of the air per unit volume, then the relation between the weight W,W1,W2 can be written as:

$W2<W_1+\omega$