A heat engine is given 120 J of heat and releases 20 J of heat to the environment. How much work does it do?

1. Work output for a cyclical process is W = Qh minus Qc. 2. Substitute Qh = 120 J and Qc = 20 J. 3. Subtracting gives W = 120 minus 20 = 100 J. 4. 140 J would come from adding instead of subtracting, and 20 J is simply the waste heat, not the work. 5. 60 J does not match this subtraction at all. 6. So 100 J is correct. _Source: OpenStax Physics (CC BY 4.0), Ch 12 "Thermodynamics", section 12.4 Applications of Thermodynamics: Heat Engines, Heat Pumps, and Refrigerators_