Hot air is less dense than cool air, so hot air will rise above cool air. Increasing the air temperature inside a hot air balloo
n makes it lighter than the surrounding air, so the balloon can lift up. The density of hot air is about 0.25 kg/m^3 less than that of cool air, which means a cubic meter of hot air can lift about 0.25 kg. What is the minimum volume of hot air needed to lift a hot air balloon carrying 800 kg?
Explanation: We are given that 1 m³ of hot air can lift a mass of about 0.25 kg. To find the volume of hot air required to lift a mass of 800 kg, we will simply use cross multiplication as follows: 1 m³ ..................> 0.25 kg ?? .....................? 800 kg
volume of hot air required = (800*1) / (0.25) volume of hot air required = 3200 m³
