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Homework Help: Friction Forces, find the coefficient of kinetic friction

  1. Jun 15, 2013 #1

    I am stuck on this question, I don't understand what to do. Any help would be great! I know that I have to use Newton's Second Law in the x and y directions.

    Greezy is pushing a very large crate of 50 kg across the floor at a constant velocity with a force of 200N. He is pushing on the crate upwards at an angle of 20 degrees.

    What is the coefficient of kinetic friction between the ground and the create?

    I don't understand what to do with that angle that is upwards?

    Thanks again!
  2. jcsd
  3. Jun 16, 2013 #2


    User Avatar

    Staff: Mentor

    On problems like this, you should usually start by drawing a free body diagram (FBD), showing the forces on the object. Then what do you do with the sum of the forces in each dimension (hint: F=ma)...?
  4. Jun 20, 2013 #3
    Thank you.
  5. Jun 20, 2013 #4
    You're solving for mu_k.

    In order to do that you should know what Friction Force is equal to. Plug that in and solve!
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