A balloon of air deflates and does 300 kJ of work to the surrounding air. While deflating, the air inside the balloon transfers 60 kJ of energy to the outside of the balloon. What is the total change of the internal energy of the air inside the balloon when it deflates?
Is that 60 kJ of energy in the form of heat?
delta U = q + w
q = -60 kJ
w = -300 kJ
dU = ?