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Homework Help: Finding acceleration using kinetic friction, final velocity, weight, and force

  1. Apr 1, 2010 #1
    1. The problem statement, all variables and given/known data
    A man pushes a chair that weighs 60N with a force of 25N. The chair has a final speed of 4.0m/s. and a kinetic friction of .27. What is the acceleration?

    2. Relevant equations
    i have no idea where to start, i tired this formula that had me find distance but the acceleration on the bottom doesn't rely on the velocity on the top so i figured it was wrong
    possibly: x=(Vx^2-Vox^2)/(2ax)??!?!?!

    3. The attempt at a solution
    it seems as if i am missing information/parts
    after substituting everything in to get the distance i got 5.5633m, but this question doesnt even ask for distance. I spent already over 4 hours on this 1 problem and still no luck, please help.
  2. jcsd
  3. Apr 1, 2010 #2
    F = ma right?

    So find the frictional force on the chair (coefficient of kinetic friction multiplied to the normal force) and divide by the mass of the chair. That will give you the deceleration of the chair after the man stops pushing on it.
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