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Homework Help: Free body diagrams

  1. Oct 26, 2013 #1
    1. The problem statement, all variables and given/known data

    http://postimg.org/image/i7phx5pp1/ [Broken]

    Im trying to draw an FBD for this, but I don't know how the treat the distributed load or what forces the thing at E contributes. Is it some kind of support?

    For the distributed load, I don't know what part of it the 800N/m and 400N/m refers to.

    http://postimg.org/image/bb93vnow7/ [Broken]
    And for this question, I just don't understand anything that's going on in that diagram; is the position of the bar fixed? Is the platform fixed?

    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Oct 26, 2013 #2


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    Staff Emeritus
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    Homework Helper

    In the future, please post only one problem per thread.

    Problem 1.:
    At point E, you have a roller in contact with the sloped surface. What kind of forces can a solid roller support?
    For a distributed load, you obviously have to have some kind of load distribution value in units of force/length.
    The diagram is telling you the distributed load starts at 400 N/m at the left end and increases linearly until the load is 800 N/m at the right end.
    To determine reactions, distributed loads can be replaced by equivalent point loads acting through the centroid of the load distribution.

    Problem 2:
    Neither the bar nor the platform are fixed. Read the problem statement carefully, "A man ... attempts to hold himself using one of the two methods shown."
    The platform is attached to the two sheaves and the sheaves in turn have a line attached to the ceiling and the bar. The man holds the bar so that the line will not slip out of the sheave, sending him and the platform to the ground (not shown).
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