Question

A balloon filled with helium has a volume of 25 m³ and is released from rest in air of density 1.3 kg m^-3. Determine the initial resultant force on it if the weight of the balloon and its contents is 300 N.

Answer 1

Balloon will displace air which will apply buyont force on balloon in upward direction.

Weight of the balloon is in downward direction. Therefore the Initial resultant force on balloon will be difference of these two forces.

Buyont force = weight of air displaced by the balloon

= volume of the air displaced x density of air x g

= 25 x 1.3 x 9.8

= 318.5 N

Since weight of balloon is 300 N therefore

Resultant force on Balloon = 318.5 - 300 = 18.5 N

Answer: Initial Resultant force = 18.5 N