Lesson 1.7: Determining Stopping Distance

The ocean liner Titanic required a distance of over 700 m to come to a stop from a cruising speed of about 33 km/h. Compared to this ship, a motor vehicle is nimble—even when it’s going much faster, a motor vehicle can be stopped in a fraction of the distance needed by the ocean liner. Nevertheless, determining a motor vehicle’s stopping distance is critical for safe driving.

• Read pages 214 to 215 of the textbook.  Work through Example Problem 1.19.  Do Practice Problem 38 and check your answers with those in the “Practice Answers” in the online course.

Traffic safety engineers must take into account the stopping distances needed by vehicles.  You will see that solving for the braking distance involves two steps.  first time should be calculated, then displacement.

• Starting at “Controlling Traffic at Intersections,” read pages 216 to 218 of the textbook.   Work through the Example Problem.  Do Practice Problems 39 and 40 and check your answers with those in the “Practice Answers” .

Sometimes a traffic light seems to take forever to change, especially if you are waiting for it to turn green. However, the lights are timed by traffic safety engineers for the most favourable and safe traffic flow. The yellow light, which indicates that the red light is about to come on, has to be on just long enough so drivers can safely avoid being in the intersection when the red light comes on. The next investigation is about the functioning of yellow lights at actual intersections. This investigation is limited to questioning and proposing a design for the investigation. These skills are fundamental to the application of science to new situations.   If you have an interest in this topic you may want to try this activity.  

 

• Read “1.7 Summary” on page 220 of the textbook. Then, complete question 4 and check your answers with those in the “Practice Answers” .