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Homework Help: Help solving a torque problem

  1. Apr 13, 2008 #1
    |.......... / ...|
    | ... /..........|
    |../ ...........M

    The mass (M) is 430kg and is hanging from a rope (second vertical line). The distance between the anchor points is 1.9m (the length of the first vertical line) and the horizontal support cable (horizontal line) is 2.5m long. The uniform beam has a mass of 85kg (the diagonal line) and if the mass of the cable can be ignored, find T the tension force in the cable and the force of the hinge on the beam. (dots are insignificant just typed them to avoid the reformatting of the diagram once submitted).

    Can anyone show me how to solve this, I have no idea where to start since we only had three classes on torques and I missed two.
  2. jcsd
  3. Apr 13, 2008 #2
    torque is equal to rXF where r is the distance from the point and f is the force acting at that distance. it should be known that only the force acting perpendicular to the distance affects torque hence the cross product. in the problem you have you have 2 downward masses(one at the center of mass for the beam and the other at the end of the beam) so you find the torques of these and counteract them with the torque created by the tension of the cable
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