14. The thermal efficiency of internal combustion engines is only around 40%. This means that only 40% of the heat that results from burning gasoline (chemical energy) is converted to mechanical energy. Consider the kinetic energy of the car and occupants from question 3. How much chemical energy was needed to accelerate the car to 76 mph?
-from question 3, the kinetic energy is 883934.05 joules
kinetic energy / 40%
the eight significant figures in the K.E number seem like a calculator artifact
... anything more than 3 or 4 sig-fig is unlikely