Determine the mass of instrument

Question

A balloon used to carry instrument for meteorogical department up into the atmosphere has a capacity of 30m³ and is filledd with hydrogen. the total mass of balloon and hydrogen is 3kg. Determine the mass of instrument that can be lifted by the balloon. (Density of hydrogen is 0.089kgm^-3 and of air is 1.29kgm^-3

Answer 1

Calculate the buoyant force on the balloon, subtract the weight of the filled balloon, and whatever remains is the weight the balloon can lift.

 

Buoyant force:

 

F_b = ρ_airVg = (1.29)(30)(9.8)N = 379.26 N

 

Weight of filled balloon:

 

W = (3 kg)(9.8 m/s²) = 29.4 N

 

Lift capability of balloon:

 

W_L = F_b - W = (379.26 - 29.4)N = 349.86 N

 

Mass that can be lifted:

 

m = W_L/g = 349.86/9.8 kg = 35.7 kg