Race car physics. Illustration of a race car, with arrows showing the force and physics involved. The arrows are colour-coded. The weight (dark blue) acts downwards from the centre of gravity. The reaction forces (orange) act upwards through the wheels. These two forces balance. The driving force of the engine (yellow) acts forwards. The forces of friction (red) act from the wheels against the forward motion. Similarly the air resistance (light blue) acts against the forward motion. The forward speed of 60 metres per second (216 kilometres per hour) is caused by the driving force left after air resistance and friction (low for a race car) are subtracted.