Bibliography references 1. http://hyperphysics.phy-astr.gsu.edu/hbase/elacol.html 2. http://www.physicsclassroom.com/mmedia/momentum/trece.cfm 3. http://www.physics4kids.com/files/motion_friction.html 4. http://www.real-world-physics-problems.com/bouncing-ball-physics.html 5. Knight, Randall Dewey. Physics For Scientists And Engineers. Boston, Mass.: Addison-Wesley, 2012. Print.