Rest energy in classical mechanics

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Discussion Overview

The discussion revolves around the concept of "rest energy" in classical mechanics, particularly in relation to its absence or presence in classical and relativistic frameworks. Participants explore the implications of taking limits in physics, the definitions of energy in different contexts, and the distinctions between classical mechanics and special relativity.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that "rest energy" does not exist in classical mechanics, emphasizing that the term is specific to relativity.
  • Others propose that in the classical limit where the speed of light approaches infinity, relativistic rest energy becomes infinite, which raises questions about the physical implications of such a limit.
  • There is a discussion about whether a system at rest can have energy, with some noting that it can contain heat energy, while others clarify that this is not the same as "rest energy."
  • Some participants highlight that classical mechanics does not impose a limit on the energy of a system at rest, allowing for potentially unbounded internal energy.
  • There is contention regarding the definitions of "classical mechanics" and "special relativity," with participants noting that these terms can have different meanings and implications in various contexts.
  • One participant suggests that the concept of energy in classical mechanics can include various forms, such as heat energy or specific energy of fuels, which contrasts with the limitations seen in relativity.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the existence or definition of "rest energy" in classical mechanics. There are competing views regarding the implications of energy limits and the relationship between classical mechanics and special relativity.

Contextual Notes

Participants note that the term "rest energy" is not standard in classical mechanics, and discussions about energy limits depend on definitions and contexts. The implications of taking limits in physics, such as ##c \to \infty##, are also highlighted as a source of confusion.

Who May Find This Useful

This discussion may be of interest to those exploring the foundations of classical mechanics and relativity, as well as individuals examining the conceptual differences in energy definitions across different physical theories.

  • #31
sweet springs said:
You will find the relation E=mc^2.

Yes, but what does that contribute to the topic? In relativity we know that E is the total energy inside the container. How do you prove that in classical mechanics?
 
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  • #32
DrStupid said:
In relativity we know that E is the total energy inside the container. How do you prove that in classical mechanics?
We now know E=mc^2 as a fact that classical mechanics or saying more accurately classical non relativistic mechanics does not anticipate, need and prove. I prefer the fact to a theory.　Don't put new wine into old bottles.
 
Last edited:
  • #33
sweet springs said:
We now know E=mc^2 as a fact that classical mechanics or saying more accurately classical non relativistic mechanics does not anticipate, need and prove.

I already wrote above that internal energy cannot be determinied in classical mechanics. That includes that classical mechanics doesn’t anticipate, need and prove E=mc². So I still do not see a new argument. Do I miss something?
 
  • #34
Now you know that non relativistic mechanics failed. I do not think you miss anything.:smile:
 
  • #35
sweet springs said:
Now you know that non relativistic mechanics failed.

I was well aware of it from the beginning (I even mentioned it in #18). You are quite off-topic if that was all you are trying to tell me.
 

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