Question

if the fuel consumption of a car, traveling at steady 60 mph, is 20 mpg what is the power produced by the petrol being burnt in the engine? Assume that the density of petrol is 0.84kg/l and the heat of combustion of petrol is 47 302kj/kg

Answer 1

Calculate how many gallons of fuel burned in the engine per 1 hour or 60 m:
60/20 = 3
Transform gallons into liters:
3 x 3.785=11.356 l
Mass of fuel is:
0.84 x 11.356 =9.539 kg
Energy that produced in the engine per 1 hour:
9.539*47302=451.214 MJ / hour