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Homework Help: Calculate the Tension and Angular Acceleration in Log After Release

  1. Apr 21, 2013 #1
    1. The problem statement, all variables and given/known data
    The uniform 69-lb log is supported by the two cables and used as a battering ram. If the log is released from rest in the position shown, calculate the initial tension induced in each cable immediately after release and the corresponding angular acceleration α of the cables.

    2. Relevant equations

    3. The attempt at a solution

    I tried first by summing the forces in the x and y directions

    ƩFx: max = TAcos(θ) + TBcos(θ)

    ƩFy: may = -mg + TAsin(θ) + TBsin(θ)

    I assumed that ax and ay are equal to 0 and then I took these two equations and tried to solve them by using the matrix function on my calculator, but it doesn't work.

    I'm now trying to take the moment about the center of the beam

    The distances I have used should be the perpendicular distances from the tensions

    ƩMG: = Iα = -TA((d+e)/s)sin(θ) + TB((d+e)/2 - d)sin(θ)

    but I'm not sure how to calculate the inertia, or if I need to calculate it at all.

    Any advice would be greatly appreciated.

    Attached Files:

    Last edited: Apr 21, 2013
  2. jcsd
  3. Apr 21, 2013 #2
    I've managed to figure it out using a normal and tangential coordinate system,
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