Example L.6.3. For this example, consider the following scenario: a cop is measuring thespeed of passing cars. She measures the speed of a red car and blue car both passing herat the same time. The red car is traveling 120 feet per second (about 80 miles per hour)while the blue car is traveling 130 feet per second (about 89 miles per hour). We will answerquestions regarding how these instantaneous rates of change can be used to estimate traveldistance.