2. Objectives After completing Unit 8: Friction and Traction, you will be able to: Explain the difference between static and kinetic friction and list the factors which determine traction. Create a VEX tire in Autodesk Inventor Professional. Have a robot ready to compete in a “tractor pull” and be proficient in making simple modifications to VEX robots. Take advantage of the principles of friction and traction to modify a robot to pull a greater amount of weight.

3. Coefficient of Friction: The ratio of maximum frictional force between two surfaces to the force holding them together. Term used to describe the "grippyness" of two surfaces meshing together. Slippery objects have a very low coefficient of friction.

4. Dimension: Parametric dimensions that control sketch size. When dimensions are changed, the sketch resizes. Dimensional constraints may be expressed as numeric constants, as variables in equations, or in parameter files.

5. Friction: The resistance that one surface or object encounters when sliding against another.

6. Kinetic Friction: The frictional force which opposes the motion of an object while it is moving.

7. Static Friction: The frictional force that opposes the motion of an object before it starts moving.

8. Traction : The friction between a, wheel, and the surface it moves upon. The amount of force a wheel can apply to a surface before it slips.

9. Tread The pattern on the surface of a tire.

10. Have a robot ready to compete in a “tractor pull,” where you can apply the lessons on friction and traction from the Unit 8: Think Phase. Make simple modifications to VEX robots.

11. Carry out pages 8-27 to 8-34 and 8-35 to 8-37

12. The end