# A balloon filled with a lighter gas occupies a volume of 1500 cu metre. Its mass (mass of material of balloon + mass of gas in it) is 1650 kg. Its tied with a rope and floating in air of density 1.3 kg/cubic metre. The pull on the rope is ?

Aug 13, 2018

The pull on the rope is $= 2940 N$

#### Explanation:

The Buoyancy force is

${F}_{b} = V \cdot \rho \cdot g$

The volume of the balloon is $= 1500 {m}^{3}$

The density of air is

$\rho = 1.3 k g {m}^{-} 3$

The acceleration due to gravity is $g = 9.8 m {s}^{-} 2$

The mass of the ballloon is $m = 1650 k g$

The weight of the balloon is $w = 1650 \cdot 9.8 = 16170 N$

The buoyancy force is

${F}_{b} = 1500 \cdot 1.3 \cdot 9.8 = 19110 N$

The pull on the rope is

${F}_{b} - w = 19110 - 16170 = 2940 N$