Question

A balloon having a volume of $4200{\text{m}}^3$ is filled with a gas at ${27}^{\circ }\text{C},and1$ bar pressure. It weighs $700\text{kg}$. If the density of air is $1.2{\text{kg m}}^{-3}$, then the pay load of the balloon is:

• A. $5040\text{kg}$
• B. $4340\text{kg}$
• C. $3500\text{kg}$
• D. $5740\text{kg}$

Answer 1

The correct option is B $4340\text{kg}$

We know density = $\frac{mass}{volume}$
Mass of air displaced = density of air $\times$ volume $=1.2\times 4200$ $=5040\text{kg}$
Total weight of the balloon$=700\text{kg}$
$\therefore$ Payload of balloon = mass of air displaced - mass of the balloon $=5040-700$ kg $=4340\text{kg}$