In one cycle of operation of the internal combustion engine, when fuel is burned in the cylinder

In one cycle of operation of the internal combustion engine, when fuel is burned in the cylinder, an energy of 50 J was released and the combustion products transferred 30 J of energy to the atmospheric air. What mechanical work did the piston do?

The mechanical work done by the piston can be calculated using the formula:
A = Q1 – Q2, where Q1 is the energy released during fuel combustion (Q1 = 50 J), Q2 is the amount of energy released into the atmosphere (Q2 = 30 J).
Let’s calculate the value of mechanical work:
A = Q1 – Q2 = 50 – 30 = 20 J.
Answer: The piston performed work equal to 20 J.