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Homework Help: Physics Forces question

  1. Nov 7, 2013 #1
    1. The problem statement, all variables and given/known data

    Block is pushed across a horizontal surface with a coefficient of kinetic friction of 0.15 by applying a 150N horizontal force

    the block accelerates at a rate of 2.53m/s^2 find the mass of the block

    2. Relevant equations

    Uf=ff/fn f=ma

    3. The attempt at a solution

    0.15=?/fn f=m2.53

    I tried crazy solutions but no progress

    The TB answer is 38kg. I have no idea what this 150N of force is, i tried using it as the net force or frictional force but it didnt work, what is it and what do i do?
  2. jcsd
  3. Nov 7, 2013 #2
    0.15 is the coefficient of friction. So in this case the frictional force will be,

    F(friction) = F(gravity)(.15)

    Try drawing a free body diagram with the applied force (that's the 150N it's talking about) and the force of friction and try to figure it out. Remember F=ma
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