Question

1. A ford engine is provided with 80,000 W power by burning its fuel. The engine produces a kinetic energy of 96 kJ for 20 seconds before its cut out.
a. Calculate the output power by the engine in watts.
b. What is the efficiency of the engine?
c. Why is there a considerable difference in the power input and output?

Answer 1

Answer: a) 4800 W  b) 6 %  c) most of the energy of fuel is converted to heat in combustion engine

Explanation: a) Power P = W/t = 96 000 J / 20 s = 4800 W

b) efficiency η = P(putput) / P(intake) = 4800 W / 80000 W = 0,06