joethedog13 joethedog13 12-03-2021 Physics contestada ist Law of Thermodynamics Question 2 of 10 What is the change in internal energy if 20 J of heat is released from a system and the system does 50 J of work on the surroundings? Use AU = Q-W. A. 30 J B. 70 J C. 30 J D. -70J