For 3 hours of run, the car, the efficiency of which is 25%, consumed

For 3 hours of run, the car, the efficiency of which is 25%, consumed 24 kg of gasoline. What is the average power of the car’s engine during this run?

Specific heat of combustion of gasoline – 24 MJ / kg;

Let’s find the amount of heat released during the combustion of 24 kg of gasoline:

Q = m * Qsp. combustion. = 24 * 24000000 = 576000000 J;

The following was spent on doing useful work:

A = Q * efficiency = 576,000,000 * 0.25 = 144,000,000 J;

t = 4 h = 14400 s;

Find the average engine power:

Wav = A / t = 144000000/14400 = 10000 W = 10 kW.

Answer: Wav = 10 kW.