A good estimate for the volume of a particular hot air balloon is 2800 m3. Suppose the total load (passengers, fuel, balloon fabric, etc.) on a hot air balloon is 724 kg. In preparing to launch, the pilot heats the air inside to an average temperature of 210 oC, giving it a density of 0.95 kg/m3 (compared to a density of 1.2 kg/m3 for the air outside the balloon). [Note! This means that the total mass of the hot air balloon is 724 kg plus the mass of the hot air in the balloon!]
How much extra mass does the pilot need to keep in the basket in order to stay on the ground while all passengers are on board?
The Attempt at a Solution
I'm really lost here. Any help would be great.