Question

If the net force on a hot-air balloon is directed straight upward, which way does the acceleration point?

• A. Downward only if the balloon if falling
• B. Upward only if the balloon is rising
• C. Upward and in the downward direction
• D. Upward
• E. None of the above: a hot air balloon floats in the atmosphere with zero acceleration.

Answer 1

The correct option is B Upward only if the balloon is rising

Given,

Direction of acceleration of balloon is upward.

Force = mass x acceleration

$\overrightarrow{F}=m\overrightarrow{a}$

Direction of acceleration is toward the net force.

Hence, direction of net force is upward if balloon is rising.