Chapter 12 Project

Full stop ahead


Assume you are traveling on a dry road and have an average reaction time. The formula d = 0.044s^2 + 1.1s gives you a safe stopping distance d in feet, where s is your speed in mi/h. Make a table of values for speeds of 10, 20, 30, 40, 50, and 60 mi/h. Then, graph the function.

Activity 2

Suppose a car left a skid mark d feet long. The formulas will estimate the speed s in miles per hour at which the car was traveling when the brakes were applied. Use the formulas to complete the table.Round to the nearest mile per hour !

The estimated speed of the car based on a skid mark with a length of 60 ft was about 40 MPH on dry road and about 28MPH on wet road.

The estimated speed of the car based on a skid mark with a length of 120ft was about 57 MPH on dry road and about 40 MPH on  wet road.


Part 2: Why do you think the estimates of speed do not double when the skid marks double in length? Based on these results, what conclusions can you make about safe distances between cars?

I think they didn't double because of the conditions of the road.

Activity 3

Suppose you are driving on a dry road with 150 ft (about 10 car lengths) between your car and the car infront of you.Use the formula from Activity1 to find the maximum speed you should be traveling in order to leave a safe stopping distance

answer: 47 mph

Activity 4

Work with a group of your classmates to plan a skit that will demonstrate what you have learned about safe distances in driving. Illustrate the relationships among reaction times, road conditions, speeds, and stopping distances. Click on the box below to view the video.

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