A quick review of the types of mechanical energy discussed last week was used to begin the class. Elastic, Chemical, and Gravitational Potential energy were reviewed, along with the formulas. That gravitational PE was determined by the force and distance moved against gravity and not the route used was demonstrated with diagrams. The formula for kinetic energy (KE) was given, and that the work done by an object is equal to the KE, so that W=KE, or expanded to fd=1/2mv2. The statement was shown; "when work is done, energy changes".