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Homework Help: Normal strain of cable through arc

  1. Dec 14, 2012 #1
    1. The problem statement, all variables and given/known data

    See attachment

    2. Relevant equations


    3. The attempt at a solution

    Ok, this is not for HW. I am preparing for a mechanics of materials class next semester. I don't understand when CB goes through the 0.3 degree arc, they say the height is still 300mm. Shouldn't it be slightly less than 300mm? If so, then I have only one angle and one non hypotenuse side, I can't figure out how to solve the rest of the new strained triangle.

    Thank you!

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  2. jcsd
  3. Dec 15, 2012 #2


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    300 mm is not the height, it is the length of the part of the rod from B to C, which is unchanged after rotation. Then use the law of cosines as shown.
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