Final answer:
The work-energy theorem describes how the work done on a system changes its energy, particularly how it equates to the change in mechanical energy, encompassing kinetic and potential energy.
Step-by-step explanation:
The accounting-like idea that the work done on a system changes the system's energy is known as the work-energy theorem. The work-energy theorem states that the work done on a system by an external force with a nonzero component parallel to the displacement is equal to the change in the system's mechanical energy. Mechanical energy is the total energy of the system, comprised of kinetic energy, potential energy, and microscopic internal energy.
According to the First Law of thermodynamics, the change in a system's internal energy can be partitioned between heat transfer and the work done on or by the system. In the context of physics, the concept of energy as the 'money of physics' can help conceptualize energy conservation. Just like money, energy may change forms but is never created or destroyed in an isolated system; it is conserved.
All these principles help in understanding how energy transfers and transformations occur, honoring the conservation of energy law, especially when examining physical processes.