Question

A blimp is filled with 5000m^3 of helium at 20°C and 1.05 bar pressure.The volume of the cabin is 30m^3 and the mass of the empty blimp structure (no helium) is 4200kg. What is the maximum additional mass that can be loaded into the cabin and still permit lift off? The surrounding air is at 1.00 bar pressure and 20°C. The molar mass of air is 28.8gmol–1

Answer 1

The condition to permit lift off.
\[ma = F- m*g = 0\] limiting case
F is the buoyant force
use pv = nRT to get n then get density of helium.