The mass of a hot-air balloon and its cargo (not including the air inside)is 150 kg.The air outside is at a temperature of 10°C and a pressure of 1 atm = 10⁵ N/m².The volume of the balloon is 600 m³.Which temperature below of the air in the balloon will allow the balloon to just lift off? (Air density at 10°C is 1.25 kg/m³. )

Question

Quizplus · Accepted Answer

To lift off, the buoyant force must equal the weight of the balloon and its cargo. The buoyant force is the weight of the displaced air, which depends on the density difference between the inside and outside air. Using the ideal gas law and the given conditions, the temperature inside the balloon must be 71°C for the balloon to lift off.

The Mass of a Hot-Air Balloon and Its Cargo (Not