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Homework Help: Friction Problems: Need Help

  1. Nov 3, 2009 #1
    1. The problem statement, all variables and given/known data
    A sled of mass 13.4 kilograms is pulled along flat snow-covered ground. The static friction coefficient is 0.334, and the kinetic friction coefficient is 0.111.
    I solved both part a and b, but im having trouble with part c.
    c. Once moving, what force is needed to accelerate the sled 2.69 meters per second per second?

    2. Relevant equations

    3. The attempt at a solution

    Im confused on how to do this.
    So Its asking for the force pushing the sled forward. Using the formula am=f
    if i plug in acceleration and the mass i get 13.4x2.69=36.046, but it said it was wrong.
    Am I missing something? Do I need to factor in frictional force?
    Would I add 14.6 to 36.046? 14.6 is the force needed to push the object at a constant velocity.
  2. jcsd
  3. Nov 3, 2009 #2

    Andrew Mason

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    Science Advisor
    Homework Helper

    Do a freebody diagram of the accelerating sleigh. What are the forces acting on the sleigh? What do they necessarily sum to?

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