#$&* course Phy 231 An example we could use to demonstrate the reason we would use the rate of change formula would be to calculate the rate at which a car is traveling. If a car is at mile marker 15 at 8:00 a.m. and at mile marker 318 at 1:00 p.m., then at what rate was the car traveling? Since the position of the vehicle changes with respect to time, our formula would be the change in position with respect to time. So 318-15=303 and there is five hours between 8:00 a.m. and 1:00 p.m. The average rate of change is (303 miles)/(5 hours) = 60.6 miles/hour. So the car was traveling at 60.6 miles per hour.