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Homework Help: Statics of rigib bodies

  1. Feb 16, 2012 #1
    Calculate the support reactions at B and E for the 9m length beam shown below.
    I have the answers at 4.71KN and 1.79KN but it is old work that i am revising and i cant remember how i got to them. One of the supports not being at the end is throwing me off. If anyone could show a rough working out it would be appreciated.

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  3. Feb 16, 2012 #2


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    You should refresh your memory on the 3 equilibrium equations
    [itex]\Sigma F_x = 0, \Sigma F_y = 0,[/itex] and [itex] \Sigma M_{any-point} = 0 [/itex].

    There is nothing going on in the x direction, so you just need the last 2 equations. The reaction forces must add up to the applied loads; but the key is summing moments about a point = 0 (hint: choose one of the reaction points as your point to sum moments about. Watch plus/minus signs).

    Please show an attempt at a solution for further assistance.
  4. Feb 27, 2012 #3
    Hi thanks for your reply

    I have (-1500 x 2) + (-3000 x 4) + (-2000 x 9) + 7B = 0
    -33000 + 7B + E= 0
    B = 33000/7
    B = 4714N

    I dont know where to go next to calculate E?
  5. Feb 27, 2012 #4


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    Yes, good. For E, the sum of forces in the vertical y direction must be zero. That will give you E. You can also find E by summing moments about B. That serves as a good check on your work.
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