Question

The weight of an empty balloon on a spring balance is W1. The weight becomes W2 when the balloon is filled with air. Let the weight of the air itself be w. Neglect the thickness of the balloon when it is filled with air. Also neglect the difference in the densities of air inside and outside the balloon.
(a) W2 = W1
(b) W2 = W1 + w
(c) W2 < W1 + w
(d) W2 > W1

Answer 1

The answers are (a) W2 = W1 and (c) W2 < W1 + w.

Explanation:

• As per the question, the air’s density outside and inside the balloon is the same.
• Thus, the air inside the balloon has the weight w, which is equal to the displaced air’s weight.
• So, the balance of the spring will not record any alteration due to the fact the balloon will involve buoyant force, which will be equal to w that stops the added air’s weight.