Car on a Level Corner

The simplest case to case to consider involves a car turning at a normal, flat intersection. Here the bank angle is zero degrees so make sure that the angle slider on the applet is set at 0^o.

As you learned earlier, there are three forces that are important in understanding the motion of a car as it rounds a corner:

• the gravitational force or weight of the car acting straight down
• the normal force or response of the road against the car acting at right angles to the road surface
• the force of friction

It is easy to see in this case that the frictional force is the only force that can act inward to supply the force needed to deflect the car from its original direction of motion into a circular turn. Let's investigate this a little closer by looking at the force needed to deflect the car moving at 15 m/s around a corner of radius 80 m. Consider these steps:

Get the acceleration

Remember that the acceleration of a body moving in a circular path is given by the expression for centripetal acceleration: