Question

In order to design safe high-speed entrance and exit ramps, highway engineers need to know about the force of friction and the maximum speeds that motorists can navigate these ramps. Suppose the coefficients of friction between rubber tires and asphalt are µs = 0.35 for static friction and µk = 0.25 for kinetic friction. You are the highway engineer charged with construction of a new freeway exit ramp. (a) Make a free-body diagram showing all of the forces acting on the car rounding the exit ramp. Be sure to indicate your chosen coordinate system and summing all of the forces that act in each direction. (Tip, before starting, take a look at what you are going to be asked to do in part (b) ... this will help you make the various decisions necessary in setting up your free-body diagram). (b) This exit ramp has a radius R = 500 m and is banked at an angle of 19? above the horizontal. What is the maximum speed vmax that a car can travel around this curve without sliding? (c) How does the maximum speed change when it is raining outside and the asphalt is wet? Explain.

Answer 1