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Homework Help: Fixed end moments is it WL^2/12 or WL/12 ?

  1. Jun 29, 2010 #1
    1. The problem statement, all variables and given/known data
    Hello Every one, well i have a question regarding the Fixed End moments, if we had a Horozontally Fixed End supported Beam, with equally distributed load (W) on the beam, and we require the moment at the fixed Ends, which Equation would i use:

    2. Relevant equations
    1: WL2/12

    3. The attempt at a solution
    my search did not give me a clear difference betwen the two, for Equation "1" this google book search :http://books.google.co.uk/books?id=...0CB4Q6AEwAw#v=onepage&q=wL/12 moment&f=false" , its a book called "Structure and architecture"
    By Angus J. MacDonald page 143, and for equation "2" pretty much every thing i learned, well at least i think i did:confused:, can someone please calrify the difference,
    thank you
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
    Last edited by a moderator: Apr 25, 2017
  2. jcsd
  3. Jun 30, 2010 #2


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    If W is the TOTAL weight of the distributed load in force units, then M= WL/12. If w is the uniformly distributed load in units of force per unit length, then M =wL^2/12. Note that W =wL. Confirm that the units of moment must be in force time length units (newton-meters or foot-pounds).
  4. Jul 2, 2010 #3
    OK thanks alot PhanthomJay, now i see how it works
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