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Homework Help: Horizontal Tension Between Two Blocks?

  1. Feb 3, 2009 #1
    1. The problem statement, all variables and given/known data
    Two blocks connected by a rope of negligible mass are being dragged by a horizontal force Fvec. Suppose Fvec = 70.0 N, m1 = 11.0 kg, m2 = 26.0 kg, and the coefficient of kinetic friction between each block and the surface is 0.100.

    Determine the tension T.

    Diagram: [ m1 ] ------Tension (T)----- [ m2 ] ------> Force

    2. Relevant equations
    F = ma

    3. The attempt at a solution
    Ok I'm assuming that the Net force pulling the two blocks = 70 N
    I really don't know where to start in this problem I've tried finding the Forces of the friction
    on the blocks and subtraced them from the net force but I'm just confused.
  2. jcsd
  3. Feb 4, 2009 #2


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    Homework Helper

    Welcome to PF.

    You got the F = ma part ok.

    So what gets accelerated?

    How much mass determines what the acceleration is right? Less of course the effects of friction.

    So how much mass is getting accelerated by the 70N?

    And if it is all accelerating together, then what must the net force be on the last mass being pulled with the tension?
  4. Feb 4, 2009 #3
    I figured it out!
    Turns out you don't even need to really now the coefficient of friction.

    All i did was find the acceleration of the blocks and use T=m1a
    and found the tension
  5. Feb 4, 2009 #4


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    Homework Helper

    The Tension needs to not only accelerate the mass, but it also needs to overcome the friction.

    Your tension then is m1*a + m1*g*μ
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