A quick review of the work formula and the physics definition of work... The fact that work is done to lift a mass above the floor, but no work is done while the mass is being held up, is due to the fact that there is no movement on the mass. The 2 categories of work were listed and discussed. The first being work done against another force, like elasticity, gravity, and friction. The second is work is done when the speed of an object changes. A few problems were presented and solved. Power was next discussed, as a rate change, involving time. Power being work done/unit of time, that is joules/sec. Joules/sec are Watts.