What physical quantity does the term "energy" often refer to in these contexts?

The term "energy" in physics is fundamentally understood as the ability to do work. This concept is central to various areas of physics, indicating that when energy is transferred or converted from one form to another, it can perform work on objects, resulting in changes in motion, temperature, or form. For example, when electrical energy is converted into mechanical energy, it can cause a motor to turn, which is a form of work being done.

In contrast, while force applied over a distance involves energy (since work is computed as force multiplied by distance), it does not capture the broader definition of energy itself. The flow of electric charge refers specifically to electrical currents and is a specific aspect of electrical energy, rather than a definition of energy as a whole. Momentum, on the other hand, pertains to the mass and velocity of an object, which is distinctly different from the concept of energy. Thus, identifying energy as "the ability to do work" encompasses the fundamental essence of energy in various physical contexts.