Achievement Task

Physics in Motion is being asked to determine if SUV engineering has create a lack of stability in the vehicle or are the accidents simply the result of poor driving habits and an invincible image created by slick advertising campaigns. An increase in the popularity of SUV vehicles has been accompanied by an alarming increase in the number of traffic fatalities due to vehicle rollovers. Many people are concerned as to the safety of this popular mode of transportation.

The Ministry of Transportation is being asked to recommend safety improvements to the auto industry. In order to make some recommendations as to the safety of SUVs the Ministry of Transportation would like you analyze the motion of both a car and an SUV.

In particular, the government wants information on the forces acting on the vehicles as they travel around a typical highway curve. Specifications of the vehicles should be available by contacting local dealers. In particular you need to focus on the centre of gravity, and then determine the static stability factor for the car. A dimensioned diagram highway curve and a free body diagram of the forces acting on the car would be useful for the Ministry in terms of proving its case.

Part A: Research

Your first step is to gather information on cars and sport utility vehicles (choose test examples for each). You may find local car dealers or the Internet to be good sources of information.

Answer the following...

1. Once a car is moving how is the car affected by Newton's first law of motion?

2. Why is friction necessary for a car to change direction?

3. A description of the relative forces on the four wheels of the car as it makes a turn.

4. A free body diagram that illustrates the forces acting on a vehicle as it goes around a curve.

5. How can antilock brake systems aggravate the rollover problem? Your staff suggests that you also read an article published in the April 2001 issue of Discover magazine, "Roll Over, The design of sport utility vehicles in enough to make the father of physics turn in his grave".

Part B: Testing and Inquiry

After a careful analysis of the information you may try to arrange a road test. If you are able find a professional driver to do the driving (one with official teacher and parental certification). Take an accelerometer with you on the trip and try and get a feel for what forces you are experiencing when accelerating, decelerating and negotiating a curve. What factors affect the stability of the vehicle? (ex. centre of gravity, wheel base, tire tread)

Part C: Analyze and Reflect

Considering your research and testing answer the following:

1. Does an SUV take more skill and attention than a car? (explain your opinion using Newtonian physics as part of your argument)

2. What safety recommendations would you make to improve the overall safety of sports utility vehicles? Arrange for appointments with the government officials from the Ministry of Transport to receive advice, discuss difficulties and discuss progress.

Part D: Communicate

Your team is responsible for creating a presentation that will be delivered to a panel of officials from the Ministry of Transportation. Develop a plan that involves dividing up each phase of the project and designating certain tasks as the responsibility of certain individuals. Devoting yourself to you're designated task and collaborating with others regarding the results of your efforts.

Your presentation should address the following areas:

1. Technical specifications for an example car and SUV product.

2. A general description of the factors that would effect vehicle stability.

3. What is the centre of gravity for a vehicle and how is it crucial to understanding vehicle stability? (What is the height of the centre of gravity for a car and a SUV?)

4. Once a car is moving how is the car affected by Newton's first law of motion?

5. Why is friction necessary for a car to change direction?

6. A description of the relative forces on the four wheels of the car as it make a turn.

7. A free body diagram that illustrates the forces acting on a vehicle as it goes around a curve.

8. How can antilock brake systems aggravate the rollover problem?