A 500 kg weather balloon is designed to lift a 1600 kg package. Remember, Weight = mass * 9.8 and Density = [mass]/[volume of water displaced]

Question

A 500 kg weather balloon is designed to lift a 1600 kg package. Remember, Weight = mass * 9.8 and Density = [mass]/[volume of water displaced]

1. What is the total mass of the balloon and the package?
2. What is the weight of the balloon and package together?
3. If the balloon is neutrally buoyant what is the buoyant force on the balloon/package?
4. What is the volume of a helium balloon if the density of helium is 1.2 Kg/L?

Answer 1

1. 500 + 1600 = 2100 kg
2. weight = mg = 2100(9.8) = 20580 N
3. Neutral buoyancy means the buoyant force = weight so it is 20580 N
4. For neutral buoyancy, 20580 N (2100 kg) of air must be displaced, so we need the density of air and helium. The value given for helium is inaccurate - should be about 0.16 kg/m³ and air density about 1.2 kg/m³. If we neglect the weight of the helium, density = mass/volume so volume = mass/density = 2100/1.2 =1750 m³.