The tractor engine efficiency is 30%. To the calculator, the useful work that the tractor engine has done

The tractor engine efficiency is 30%. To the calculator, the useful work that the tractor engine has done, having consumed 3 kg of gasoline.

These tasks: η (tractor engine efficiency) = 30% (0.3); m (mass of gasoline consumed by the tractor) = 3 kg.

Reference values: q (specific heat of combustion of gasoline) = 4.6 * 10 ^ 7 J.

The useful work performed by the tractor engine can be expressed from the formula: η = Ap / Qz, whence Ap = Qz * η = q * m * η.

Calculation: Ap = 4.6 * 10 ^ 7 * 3 * 0.3 = 41,400,000 J (41.4 MJ).

Answer: The tractor engine has done 41.4 MJ of useful work.