Question

A hot air balloon weighing 30N is tied to the ground by a string to prevent from floating off the ground.the volume of the balloon is 20m3 and the density of air is 1.3kgm -3.Find upthrust acting on the balloon.Take g =10ms-2.

Answer 1

Given:

A hot air balloon weighing 30N is tied to the ground by a string to prevent from floating off the ground.the volume of the balloon is 20m3 and the density of air is 1.3kgm^(-3).

To find:

Up-thrust on the balloon.

Calculation:

The up-thrust experienced by the balloon is actually the buoyant force of air acting in the upward direction on the balloon.

Putting all the values in SI unit:

$\sf{upthrust = V_{in} \times \rho \times g}$

$\sf{ = > upthrust = 20 \times 1.3 \times 10}$

$\sf{ = > upthrust = 20 \times 13}$

$\sf{ = > upthrust = 260 \: N }$

So, final answer is :

$\boxed{ \red{ \large{ \rm{upthrust = 260 \: N }}}}$