Let us look in detail at energy use in cars. As an example we use the data of a regular car that has a curb weight of 1300kg. More data: the drag coefficient is CD = 0.33 and the frontal cross sectional area is A = 2m^2. The coefficient of rolling friction of a car tire on asphalt or concrete is 0.01 .

(a) Estimate how much energy is needed to compensate for rolling friction over a distance of 100 km. Assume that the car is travelling at constant speed on level road. Give you answer in MJ.

(b) Estimate how much energy is needed to compensate for drag over a distance of 100 km. Assume that the car is travelling at constant speed of 60 km/h on level road, and take the density of air to be p= 1.29kg/m^3 . Give you answer in MJ.