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Homework Help: Newton's law of motion -- crates & strings & friction

  1. Sep 25, 2014 #1


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    1. The problem statement, all variables and given/known data
    three boxes connected by strings.
    given the mass of each box, coefficient of static and kinetic friction, and a constant speed of 2.0 m/s

    I want to know how to get force by a given speed...!
    Also, at a constant speed, how do I get to know the acceleration? does a = 0? if a = 0, how can I find Forces?

    2. Relevant equations

    F = ma

    3. The attempt at a solution
  2. jcsd
  3. Sep 25, 2014 #2


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    Gold Member

    Do you understand what acceleration IS?
  4. Sep 25, 2014 #3


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    Staff: Mentor

    Start this kind of problem by drawing a free body diagram (FBD) of each of the crates. Be sure to show the frictional forces... that is how you can have a force even when the net acceleration is zero...
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