The rate of heat transfer to the surroundings from a person at rest is about 400 kJ per hour. Suppose that the ventilation system fails in an auditorium containing 2000 people.
(a) How much does the internal energy of the air in the auditorium increases during the first 20 minutes after the ventilation system fails?
(b) Considering the auditorium and all the people as a system, and assuming no heat transfer to the surroundings, how much does the internal energy of the system change? How do you explain the fact that the temperature of the air increases?