Question

A balloon of volume 800 cm3

is filled with hydrogen gas of density 9X 10-5

gcm-3

. If the empty

balloon weighs 0.3 gf and density of air is 1.3X 10-3

gcm-3

, calculate the lifting power of balloon.​

Answer 1

the lifting power of balloon = mass of air displaced - (mass of the helium gas + balloon)

mass of helium gas = volume of gas x density = 800 x 10-6 m3 x 0.09 kg/m3

so

mass of helium gas = 7.2 x 10-5 kg

and mass of balloon = 0.3 gf = 0.0029 kg

and the mass of a m3 of air will be = 1 m3 x 1.3 kg/m3

or

mass of displaced air = 1.3 kg/m3