  Motivated by real classroom discussions, we analyse the forces acting on
moving vehicles, specifically friction forces on the wheels. In usual cars,
with front-wheel drive, when the car accelerates these forces are in the
forward direction in the front wheels, but they are in the opposite direction
in the rear wheels. The situation may be intriguing for students, but it may
also be helpful and stimulating to clarify the role of friction forces on
rolling objects. In this article we also study thermodynamical aspects of an
accelerating car, relating the distance traveled with the amount of fuel
consumed. The fuel consumption is explicitly shown to be Galilean invariant and
we identify the Gibbs free energy as the relevant quantity that enters in the
thermodynamical description of the accelerating car. The more realistic case of
the car's motion taking into account the dragging forces is also discussed.
