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Homework Help: Circular Motion 12th grade physics

  1. Apr 25, 2010 #1
    From the diagram above, solve for the reaction at point A. and the tension in the cable that is attatched at point C. Assume the bar is mass-less. Block B has a mass of 124 kg. The distance from point B to point A is 3.2m, from point A to point D is 1.3 m, and point D to point C 2.1 m. The cable attaches to the wall forming a 30 degree angle with the wall.

    This is an equation with an attached pic from my highschool physics class. It was a "just for fun" problem that the teacher does not expect us to be able to figure out, but I wanted to know if someone could give me some suggestions, I really have no idea. This is not for a grade, other wise I would have attempted it in a more vigourous level.

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  3. Apr 25, 2010 #2


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    It is usually best to break up forces into their x and y components. I don't know if you have studied free body diagrams, but if yes, you should draw one of the 'block/ cable/ support at A' system, isolating it from the wall. Note that the horizontal and vertical components of the cable force are trig related. Then use the 3 equations of equilibrium to solve for the cable tension and support reactions.
  4. Apr 26, 2010 #3
    Thanks so much! I will be working on this later on today, I will let you know if I have anymore questions
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