Benson, T. (2014, June 12). Newton's Laws of Motion. Retrieved November 24, 2014, from http://www.grc.nasa.gov/WWW/k-12/airplane/newton.html

Duffy, A. (1998, April 24). Friction. Retrieved November 23, 2014, from http://physics.bu.edu/~duffy/py105/Friction.html

Knight, R. (2013). Physics: For Scientists and Engineers. Upper Saddle River: Pearson.

Nave, C. (2012, January 1). Rotational-Linear Parallels. Retrieved November 23, 2014, from http://hyperphysics.phy-astr.gsu.edu/hbase/mi.html

Vawter, R. (2010, September 1). Center of Mass. Retrieved November 23, 2014, from http://faculty.wwu.edu/vawter/PhysicsNet/Topics/Momentum/TheCenterOfMass.html