This paper is a look at the physics behind car racing. We look look at how we can use physics to select tires, how physics can help predict how much traction we will have, how physics helps modern cars get there extreme speed, how physics lets us predict the power of an engine, and how physics can even help the driver find the quickest way around the track.
Tires are the most important part of race or any car for that mater. (Physics of Racing) After all they are the only thing that is contact with the ground! Tires work by having a high coefficient of friction. Some slicks have a friction coefficient grater then 1! (Physics of Racing) Typical normal street tires have coefficient of about .5 to .6 . In physics we learned that friction was equal to mew times the normal force. Since race cars are typical much lighter then normal cars, they use tricks to increase the downward force on the tires. Some drag tires run really low pressure, other drag cars tune the car to lift the front wheels to put all the weight on the rear tires. Indy cars use a wing to generate down force, and ventures to suck the car to the ground. (How to Make Your Car Handle)
Take a look at a good example of a slick and a normal street tire. The little holes on the slick are to check how much slick is left on the tire, since tires tend to ware on the edges faster. The gaps in the normal tires allow the tire to transfer water away from the tire, so the tire can make contact with the road. Goodyear makes a slick that is grooved for racing in the rain, but only crazy (Indy, F1) people do that!
The circle of traction is a important racing concept with applications from physics. From newtons equation f=ma we know that the more force we apply to an object of constant mass (the car) it will accelerate faster. Since the car moves in two dimensions its accelerations are in vector form. If we are going to keep the tires from sliding, the sum of the acceleration and turning vector's magnitude can't be larger then the max force of our tires. This max force of traction forms a circle, with the radius forming a circle. (Chassis Engineering) You can see why if your on the brakes you have less traction for turning. We know this from real life too, since if you have a really tight turn in a car, if you slam your breaks your going to slide off at a tangent to the curve.
Aerodynamics have really changed modern racing. Most high speed cars use a large wing like the McLaren to make the body of the car push down harder on the tires. This effectively increases the normal force on the tire to increases the frictional force of the tires. (Physics of Racing) Of course this large wing creates drag, so most wings have a low angle of attack. (Auto Math) Some Formual 3000, F1, Indy, and GTP cars use large scoops on the side that are shaped like an hour glass, with a small hole under the body. This creates a low pressure system under the car and sucks the car to the road. ...