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Homework Help: Shear and Moment Diagram Equations

  1. Apr 15, 2017 #1
    1. The problem statement, all variables and given/known data
    Write the shear and moment diagram equations and graph them.

    2. Relevant equations

    3. The attempt at a solution
    I attached my attempted solution in a pdf (I know the last section of the moment diagram is supposed to be parabolic, I accidentally drew a straight line instead). I can't figure out what I'm doing wrong. When I use the method where you just calculate the areas of the shear diagram to get the moment diagram, I get the correct answer. But when I use my moment equation I get 180 instead of 90. I feel like I've had previous problems where my answer was off by a factor of 2. I would really appreciate if someone could catch where I'm making a mistake!

    Attached Files:

  2. jcsd
  3. Apr 15, 2017 #2
    It appears to me that your shear diagram is incorrect. The reaction at the left end is upward, so the diagram should initially start positive. See if that helps.
  4. Apr 15, 2017 #3
    Sorry its kind of hard to see in the pdf, but its -6.25 kip. I should have just drawn it downward instead of tacking on a negative sign.
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