1 Horsepower= Horsepower is a unit of power. Power describes how fast energy is exchanged; a use of energy divided by how long it takes to use that energy 2. Energy= as the capacity of doing work. 3. Power= the rate at which electrical energy is delivered to a load 4. Power Law= is a functional relationship between two quantities, where a relative change in one quantity results in a proportional relative change in the other quantity, independent of the initial size of those quantities: one quantity varies as a power of another. 5. Kilowatt hour= this unit of measure considers the use of energy at the rate of 1000 watts per hour.