일반물리학 1 — Entropy and the Second Law of Thermodynamics: Problem 7

7 The efficiency of a particular car engine is 20% when the engine does 8.2 kJ of work per cycle. Assume the process is reversible. What are (a) the energy the engine gains per cycle as heat \(Q_{gain}\) from the fuel combustion and (b) the energy the engine loses per cycle as heat \(Q_{lost}\)? If a tune-up increases the efficiency to 31%, what are (c) \(Q_{gain}\) and (d) \(Q_{lost}\) at the same work value?