Physics is Fun Teacher Guide for Racing

Episode Description
In Physics of Racing, Jessica and Cheston meet veteran NASCAR driver Bobby Allison at the Talladega International Motorsports Hall of Fame, and later learn the role of physics in auto racing from NASCAR driver Lyndon Amick. Physics is not only applied to aerodynamics and speed, but to the safety of all drivers.

Concepts Covered
Aerodynamics - the study of the motion of a gas (in this case air) on objects and the forces produced

Downforce - a vertical force directed downward, produced by the airflow
around an object; Down Force is typically created by a device like a wing or front air dam or rear spoiler.

Newton's First Law of Motion - an object in motion tends to stay in motion and an object at rest tends to stay at rest, unless the object is acted upon by an outside force

Newton's Third Law of Motion - for every action there is an equal and
opposite reaction

Drag - a force in opposition to the forward motion of an object, caused by friction

Vocabulary

Front Air Dam - device used to control movement of air over or under the front of the car. Making the front air dam higher gives the front of the car less downforce. Making the air dam lower to the ground gives the front of the car more down force.

Rear Spoiler - designed to give or take away down force on the rear of the car. If you raise the rear spoiler, you will create more down force on the rear of the car. The trade off is that the higher spoiler also creates more drag on the back of the car. If you lower the rear spoiler you will have less downforce, but you will also have less drag.

NASCAR rules determine the height of the spoiler. On fast high banked tracks like Talladega where downforce is not as important, NASCAR will raise the spoiler to create drag and slow the cars down. On short tracks where downforce is important, NASCAR will lower the spoiler, giving the car less downforce in the corners, and making the drivers go a bit slower.

Preview Discussion
Have you haver been to a car race or seen one on television?
What does the racer consider to make a car go fast?
How do they make the car safe, as well as, fast?

Post Viewing Activities

Newton's First Law of Motion
Objective: Using racing and related support material, students will gain an understanding of Newton's First Law of Motion.
Materials Needed
Egg ( a raw egg will provide a greater a visual, but also a mess; a
soft-boiled egg will improve the mess, but provide a lesser visual; )
Large Rubber Bands or Duct Tape
Skateboard, small toy truck, wagon.
*Any item that will role across the ground and that an egg can be placed in*
Playdough or anything that can hold the egg stable for the exercise.

Class Time: One class period; May be done outside using an exterior wall.

Lesson Background
Newton's First Law of Motion states: "An object in motion tends to stay in motion and an object at rest tends to stay at rest, unless the object is acted upon by an outside force". The idea here is to understand how this law reflects the importance of wearing seat belts. The egg represents a person riding in a car without a seat belt. In this demonstration, the egg, will stay in motion after the object it is traveling on hits another object. The egg is only stopped when it meets with an object, or outside force. This is a perfect example of what can happen to people in an automobile crash when they don't wear seatbelts.

Step-by-step
1. Mold a large piece of playdough or other object that will hold or cradle the egg. The idea is to give the egg enough support, so that it will stay on the transportation system while it is moving. The playdough or other support material can be held in place by large rubber bands or tape.

2. Before you place the egg carrier on the transportation system you're
using, practice with it first. The idea is to push the transportation system into a wall or solid object that will represent a car hitting an object.

3. Place the holder onto the wagon or other device. Make sure it is secure.

4. Place the egg in the holder. The egg should be secure, so it won't roll off, but not restrained. The egg is supposed to fly out of the holder when the transportation system hits the solid object.

5. From approximately five feet away, push the transportation system with the egg on it into a solid object, such as a wall.

6. When the transportation system hits the solid object, like a wall, the egg should fly out. What happens to the egg? Try the same experiment at different speeds.

7. Finally, repeat the experiment, but have students invent ways of
restraining the egg, on the transportation system. What happens to the egg now, when the transportation system hits the wall? Try the experiment at different speeds.

Conclusion
This demonstration should illustrate the need to use a seatbelt at all times in a car and why race drivers are so well restrained in the cars. If you are riding in a car at 50 mph, that means your body is traveling at the same speed. When the car hits an object, your body will continue at 50 mph until another force acts upon your body. This principle of physics is the reason people can actually fly through the windshield or hit the dashboard and do such serious damage. The seat belt will hold your body at the same speed of the car. When it slows from the impact, so will you. If you're not connected to the car, then your body will continue to move forward until it hits an object that will overcome the force of your body's forward movement.

Newton's Third Law of Motion
Objective: Using racing and related support material, students will gain an understanding of Newton's Third Law of Motion.

Materials Needed
Chalk board, white board, or picture of race car on which you can draw
Model or diecast car
cardboard or wood strips
rubber bands, glue, velcro, or other means of attachment

Class Time: One class period

Lesson Background
Newton's Third Law of Motion states that for "every action there is an equal and opposite reaction." A rear spoiler or front air dam is placed on a car to help provide down force or slow the car down. When air hits the rear spoiler, two things happen. First, the air hitting the rear spoiler causes drag on the car. The higher the spoiler, the more the drag. The reaction of the drag on the car is to slow it down. Second, when air hits the spoiler it is deflected up. According to Newton's Third Law, if the air is deflected up, then the car is deflected down. When the air hits the spoiler the other reaction force is drag.

In NASCAR racing the height and angle of the rear spoiler and front air dam is the same for all teams. In many cases, they will raise the spoilers on fast tracks to slow the cars down. On slow tracks they will lower the rear spoiler to slow cars down.

The reason is that on large fast tracks the teams want as little drag on the back of the car as possible. On slow tight tracks teams want as much down force to make it through the turns as fast as possible. By taking away the down force, drivers must go slower around the turns, decreasing speeds.

The front air dam works in just about the same way. The closer the air dam is to the ground, the more down force on the front of the car. If you raise the front air dam, the car will be faster on the straight, but will have less down force on the corners. The same thing applies as the rear spoiler.

Step-by-step

1. Draw a picture to demonstrate how air moves over the rear spoiler or front air dam.

2. In small groups, have students use a piece of cardboard or strip of wood to simulate a spoiler. Insruct them to change the angle or height of the spoiler and explain what effect it should have on the car, according to the application of Newton's Third Law.

Conclusion

In many ways, racing is a study of action/reaction forces. From changing the air pressure in the tires, to making other adjustments to the car, everything is based on an understanding of the reaction of the car to the modifications. Although NASCAR controls the height and angle of the front air dams and rear spoilers, crews still have to understand the reaction the car will have to both the rear and front of the car.

Activities provided by Rev It Up: Racing Across the Curriculum

Newton On Racing
Race over to these sites for more information:

Physics of Racing Series
http://members.home.net/rck/phor

50 Years of NASCAR
http://www.nascar.com/nascar50/index.html

Lyndon Amick's Homepage
http://www.lyndonamick.com/

International Motorsports Hall of Fame http://www.bham.net/sports/sports.html