An airship contains 6*10^3 m^3 of helium. Helium has a density of 0.180 kg m^-3. Given That the air has a density of 1.20 kg m^-3 at the height at which the airship is floating in equilibrium, what load is the airship carrying?
The Archimedes force for this airship can be find as Fa = (rho_air - rho_helium)*g*V
where V=6*10^3 m^3 is volume of helium, g=9.8 m/s^2 and (rho_air - rho_helium) is the difference of densities. Therefore
Fa = (1.2-0.18)*6*10^3*9.8 = 59976 N It means, that this airship can carry 59976/9.8 = 6120 kg