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Homework Help: Need help calculating the tension in the string of two boxes with friction

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

    Two boxes are connected by a cord running over a pulley. Box A sits on a table and has a mass of 5.0 kg while box B hangs
    freely and has a mass of 2.0 kg. Box A moves to the right and box B moves
    downwards. If the coefficient of kinetic friction between box A and the table is
    0.20, what is the acceleration of the system and the tension in the cord? You
    may assume that the cord remains taut and does not stretch.

    2. Relevant equations

    3. The attempt at a solution
    The first part is fine i get 1.4m/s2

    then the second part to calculate tension im lost with what to do:


    where m1= 5kg
    m2= 2kg

    the answer is supposed to be 17N but when i solve for T i dont get anywhere near that...

  2. jcsd
  3. May 14, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    You got your m1 and m2 reversed.
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