A car weighs 1500 kg and the friction is 8% of it's weight. The car is going 90km/h and the motors thermal efficiency is 30%. One liter of gas contains 8,7kWh. How much gas does the car need for every kilometer?
EDIT: Maybe I should rephrase this. I have an idea how to solve it it's just not right. My basic idea is to just count the amount of energy the car needs and divide it by the energy that the gas gives.