Determine the efficiency of the tractor engine, which required 1.5 kg of fuel with a specific heat of combustion

Determine the efficiency of the tractor engine, which required 1.5 kg of fuel with a specific heat of combustion of 4.2 * 10 ^ 6 J / kg to perform work 1.89 * 10 ^ 7 J / kg.

Ap = 1.89 * 10 ^ 7 J.

m = 1.5 kg.

q = 4.2 * 10 ^ 6 J / kg.

Efficiency -?

The efficiency of the tractor efficiency shows what part of the work expended, expressed as a percentage, goes into useful work.

Efficiency = Ap * 100% / Az.

The spent work Az will be the amount of heat Q, which is released in the tractor engine during fuel combustion: Az = Q.

Q = q * m.

Efficiency = Ap * 100% / q * m.

Efficiency = 1.89 * 10 ^ 7 J * 100% / 4.2 * 10 ^ 6 J / kg * 1.5 kg = 300%.

The efficiency cannot be more than 100%, so an error was made in the problem statement.

Answer: a mistake was made in the problem statement.