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Homework Help: Beam resting on wide supports with a distributed load

  1. Oct 2, 2009 #1
    1. The problem statement, all variables and given/known data

    A beams is 3.0m long, it rests on two wide supports. The support A is 0.5m wide. Support B is unknown. Point A is taken to be the end of the beam on your left.

    Support A has a loading intensity of 75 N/m.

    The load on the beam acts with a force of 300N, 2.0m from point A.

    The question requires working out the width AND loading intensity of support B, such that the "resultant force and couple moment" about point A is Zero.

    2. Relevant equations


    3. The attempt at a solution

    I cannot find any examples that use wide supports on beams, or involve loading intensities on those supports. All examples I have found use pivot points! How do I account for the fact that the beam is resting on wide supports, not pivot points, and how would I go about working out the dimensions for Support B and it's loading intensity?

    Can someone please point me in the right path?
  2. jcsd
  3. Oct 2, 2009 #2


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    Homework Helper

    Think of the supports as uniformly distributed loads in the opposite direction of the 300N load. The 2 unknowns are the width of the load and intensity at B (the problem doesn't state but you can assume point B is the end of the beam). You are asked to find the width and intensity of the support load at B such that the resultant force is zero and moment about point A is zero. Two equations and two unknowns.
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