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What is Energy

  1. May 2, 2008 #1
    Is it correct to say that the core idea of energy as the ablity to do work is the same for Newtionian Physics and Relativity?
     
  2. jcsd
  3. May 2, 2008 #2

    Nabeshin

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    Well under relativity energy and mass are equivalent... so something's got to change there, because that would imply the statement "Mass is the ability to do work". Strange.
     
  4. May 3, 2008 #3
    mass is the measure of resistence changes in motion...hence, the capacity to do work is the same as the measure of resistance to chances in motion
     
  5. May 3, 2008 #4
    Yes, energy can be defined as the capacity to do work in relativistic as well as Newtonian physics, ...and yes, it leads to weird conclusions. That's relativity. :smile:
     
  6. May 4, 2008 #5
    I am writing a paper on the philosophy of science and I am arguing that the core concept of energy (the ability to do work) is the same for Newtonian Physics and Relativity and that the primary difference is that Einstein discovered the connection between mass and energy which was unknown to Newtonian science. Do you agree with this?
     
  7. May 4, 2008 #6
    Core? Primary? That's a matter of opinion. There are several equivalent ways of defining energy.

    But since it's a philosophy paper, argue whatever you want. ;)
     
  8. May 4, 2008 #7
    If you believe that use of such terms as 'core' and 'primary' are a matter of opinion then I withdraw them. I am interested in matters of scientific fact. Please bear in my mind that i am not asking whether the defintion of energy as the ability to do work happens to apply to Newtonian Physics and Relativity. I am asking how those terms are understood and function from a Newtonian and Relativistic veiwpoint.

    Suppose that I re-phrase the statement this way...

    the concept of energy (the ability to do work) is common to Newtonian Physics and Relativity and the critical difference is that Einstein discovered the connection between mass and energy which was unknown to Newtonian science. or do you believe that this statement is open to debate?

    More specifically, i am interested in what changed and did not change in the concept of energy with regard to Newtonian Physics and Einstien.
     
    Last edited: May 4, 2008
  9. May 4, 2008 #8
    That is one of the critical differences, and it's easy to argue that it is the critical difference. Your paper is on solid ground.

    But when you go beyond the equations to what the equations mean, everything is open to debate. That's what makes philosophy fun. :wink:
     
  10. May 4, 2008 #9
    I would say that it's the "stuff" that makes the universe.
     
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