In this chapter, we will learn how to characterize and quantify the energy within a system and the energy crossing the system boundary. We classify the energy within a system into one of three categories: Kinetic Energy, Potential Energy, and Internal Energy. Because all mass has energy associated with it, anytime mass crosses the system boundary, energy also crosses the system boundary. Energy can also cross the system boundary due to work or heat transfer, which are both modes of energy transfer but are not forms of energy. We will learn that anytime that mass crosses the system boundary, a form of work called flow work is done. The amount of flow work associated with mass crossing the system boundary is a property of the substance, and we will combine the internal energy and flow work to form a property called enthalpy.
The SLS uses a tremendous amount of energy during its launch. Some of the energy is used to do work to lift the rocket into space. The rest of the energy is lost through heat and mass transfer to the surroundings.