A car moves on a flat road with a steady velocity of 80 km/h. It consumes gasoline at a rate of 0.1 liter per km. Friction of the tires on the road and bearing losses are proportional to the velocity and, at 80 km/h, introduce a drag of 222 N. Aerodynamic drag is proportional to the square of the velocity with a coefficient of proportionality of 0.99 when the force is measured in N and the velocity in m/s.
What is the efficiency of fuel utilization? Assuming that the efficiency is constant, what is the ‘kilometrage” (i.e., the number of kilometers per liter of fuel) if the car is driven at 50 km/h?
The density of gasolone in 800 kg per cubic meter, and its heat of combustion is 49 MJ per kg.
