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Homework Help: Forces/Tension Problem

  1. Sep 3, 2008 #1
    1. The problem statement, all variables and given/known data

    3 blocks A B C are connected by strings as in attached image. The block C is descending with constant velocity. i've worked out the tension in string A B to be 7.31N. The coefficient of kinetic friction between each block and the surface is 0.36 and block a b weighs 20.3N each. I've also calculated the weight of C to be 25.3N. The last part of the question asked for the acceleration of block C if the rope between A B is cut.

    2. Relevant equations

    Link to figure

    http://b.imagehost.org/view/0603/YF-05-56.jpg [Broken]

    3. The attempt at a solution

    I figured that if the rope was cut, the resultant force would be = t in A B which is 7.31N, working out to an equation 7.31 = (25.3/9.80) * acceleration. However the answer is wrong. The question did not provide a numerical value for g so i was wondering if i shouldnt have used 9.80. Any help would be much appreciated thanks.

    Attached Files:

    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Sep 3, 2008 #2


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    Staff Emeritus
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    If the rope between A & B was cut, wouldn't the tension in AB be necessarily zero? Wouldn't the tension between BC be more relevant to the acceleration of C?
    Last edited by a moderator: May 3, 2017
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