The discussion clarifies that "rest energy" is not a concept in classical mechanics, as it is primarily associated with relativity. In classical mechanics, a system at rest can have energy, such as heat energy, but this is not referred to as "rest energy." The term "unlimited" energy was debated, with participants noting that while classical mechanics does not impose limits on energy, it lacks the framework to define rest energy as in relativity. The conversation emphasizes the distinction between classical mechanics and special relativity, particularly regarding energy definitions and limits. Ultimately, there is no equivalent of "rest energy" in classical mechanics, and energy concepts differ significantly between the two frameworks.
