If the starting volume of a hot air balloon is 55,500 m3and the initial temperature is 21 °C, what is the temperature inside the balloon is the final volume is 74,000 m3.

Explain why the volume of the balloon increases when temperature is increased in terms of average
kinetic energy, collisions and volume. Explain how the balloon is actually able to lift off the ground
in terms of density. (Useful info: density of hot air is 0.946 kg/m3 and the density of normal (ambient
air) is 1.2 kg/m3.)