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Homework Help: Rope pulling mass w/ friction

  1. Oct 26, 2008 #1
    1. The problem statement, all variables and given/known data A rope that is 30° to the horizontal has a tension of 150 N. It is used to pull a 40kg packing crate on a rough sruface through a distance of 6 m. If the crate moves at a constant speed, find the work done by friction.



    2. Relevant equations

    Energy formulas, not kinematic.


    3. The attempt at a solution

    I'm at a loss for what step to take after drawing my F-B-D. I've got it set up, but just brain-farting what next. I've thought over this problem, and I know it's a very simple one, but I just can't comprehend it or something.
     
  2. jcsd
  3. Oct 27, 2008 #2
    "constant speed" is question-code for something...
     
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