Bibliography
-"Friction", 04/16/03. http://hypertextbook.com/physics/mechanics/friction/.
-"Explaination of Friction: Physics." 4/15/03. http://www.physicseq.com/force/frictionhelp.html
-"Physics 106 - How Things Work". 4/13/03
-Serway, Raymond and Beicher, Robert.Physics: For Scientists and Engineers. United States, Thomson Learning. 2000.
-Watterson, Bill. Indispensible Calvin and Hobbes, The. New York, Scholastic Inc. 1992
* All pictures were scanned and modified as needed.