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Defining a weight process

  1. Jun 25, 2010 #1
    Here we go again! :smile: I am taking a graduate thermodynamics course and I feel like I am in physics 1 all over again. The definitions that I took for granted early on in my education I am really wanting to make sure that I have a firm understanding of before I progress. I am reading from the thermodynamics text by Gyftopoulos and Baretta. I am reading the energy chapter and he is in the midst of defining a weight process. I think that I understand it for the most part, but I am getting hung up on some of the details (the devil is in the details!).

    Here are the two paragraphs that I am currently reading:

    Doc-6_25_103_45PM-page-1.png
    Screenshot2010-06-25at42554PM.png

    I believe he is just intuitively proving the Work Energy theorem, but I am getting a little lost. Why is the force F constant? I see that we have attached the pulley to the point mass in its final state where it has velocity, but are they calling that V1 or v2? I believe that they are calling it V1. That is, by using the term annulled, it appears that they are working backwards in a sense. They are using the weight to bring the point mass from its final state back to its initial.

    I am also confused by the whole ||W| - Mg| / Mg << 1 thing. What is that all about now?

    Sorry if these seem stupid, but I really need to talk this out with someone. I know from other students that this entire book takes a really different approach to thermodynamics, so I really want to stay on top of the definitions used early on.

    Thanks!
    Casey
     
  2. jcsd
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