The mass of a hot air ballon including its cargo is 320 kg. the hot air inside it has a density of 1.19 kg/m^3. the density of the outside air is 1.29 kg/m^3. what is the buoyant force acting on the ballon when it is floating above the ground?

40454.4 N

Explanation:

mass, m = 320 kg

density of hot air, d = 1.19 kg/m^3

density of cold air, d' = 1.29 kg/m^3

Volume of the balloon, V = mass / density

V = 320 / (1.29 - 1.19)

V = 3200 m^3

So, buoyant force

F = Volume x density outside x gravity

F = 3200 x 1.29 x 9.8

F = 40454.4 N

thus, the buoyant force is 40454.4 N.