Review definition of kinetic energy. Discuss formula as KE= 1/2 MV2.. Review that work is fxd and work is done to counter kinetic energy. Discuss work = kinetic energy, and therefore fd=/12mv2. Discuss that when work is done, kinetic energy changes... Introduce force-force of friction x distance kinetic energy. Determine that an object moving at constant speed, just overcoming the force of friction, exhibits a net force of zero and KE or zero.