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Beam on supports with a joint

  1. Mar 16, 2015 #1
    1. The problem statement, all variables and given/known data
    Pay attention that the left support A is a fixed axis and the right, B, is a free moving axis. C is a joint.
    The left beam (to the joint): 2m, 6[kN], the right beam: 3m, 10[kN]. What is the force F.

    2. Relevant equations
    Moments: ##M=F\cdot L##

    3. The attempt at a solution
    To support he right beam 5[kN] must be applied upwards on the joint. moments around A:
    $$1.4\cdot F=6\cdot 1+5\cdot 2$$
    $$1.4\cdot F=16\rightarrow F=11.43$$
    It should be F=10

    Attached Files:

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  2. jcsd
  3. Mar 16, 2015 #2
    I assume C is a pinned joint?

    It seems to me that there is a mechanism where joint C would need to move up in order to develop a sufficient load from the right side beam for equilibrium.

    You may want clarify things and draw a free body diagram with all the reaction forces and beam lengths labeled.
  4. Mar 16, 2015 #3


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    Staff: Mentor

    @Karol I get your answer.

    I think you'll find that if you change that 1.4m to 1.6m your answers will all be in agreement with the book. :wink:
  5. Mar 16, 2015 #4
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