Question

Why does a balloon stop rising when it attains a certain height?

• A. The air pressure diminishes with height and hence at a particular height the equilibrium is reached
• B. At a particular height, the net gravitational force on the balloon is zero, and hence it remains balanced
• C. The balloon will stop rising when the up-thrust on it becomes equal to its weight
• D. At a certain height the pressure inside the balloon is in equilibrium with the pressure outside it

Answer 1

The correct option is C The balloon will stop rising when the up-thrust on it becomes equal to its weight

When upthrust is equal to downthrust, the balloon will stop rising. Here the downthrust is equal to the weight of the balloon.