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Homework Help: Find beta angle

  1. Jul 15, 2013 #1
    1. The problem statement, all variables and given/known data

    The position of the L-shaped rod shown is controlled by a cable attached at point B. Determine the angle, β, in terms of θ.

    3. The attempt at a solution

    From the FBD attached, I was able to get:

    β = tan-1([itex]\frac{0.24sinθ - EF}{0.24cosθ+0.32}[/itex])

    How can I determine what EF is? Is it possible to get an actual number? FG = 0.160

    Attached Files:

    Last edited: Jul 15, 2013
  2. jcsd
  3. Jul 16, 2013 #2

    Simon Bridge

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    Is the beta angle supposed to be the angle the cable BE makes to the vertical?

    Then I think there is something not quite right about your diagram ...
    F is vertically above the pivot of the beam and level with the top of the pulley?
    It is 160mm horizontally from F to the center of the pulley.

    It looks like you'll need the diameter of the pulley.
  4. Jul 18, 2013 #3


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    aaronfue: FG is not 160 mm. FG is simply AB*sin(theta), whereas EF = 160 mm.

    Here are my current thoughts. Theta can be any value; it is given. Given theta, then I think beta can be any value, depending on the pulley radius. You are given the pulley axle horizontal location, which is EF = 160 mm.

    But are you given the pulley radius? If not, I am currently thinking beta will also be a function of pulley radius, r.
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