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Homework Help: Coefficient of friction problem

  1. Dec 12, 2011 #1
    1. The problem statement, all variables and given/known data

    a body of mass 10 kg lies on a rough horizontal surface with an acceleration of 5 m/s and when the horizontal force us doubled , it gets an acceleration of 18 m/s^2. Then the coefficient of friction between the body and the horizontal surface is:

    A) 0.2 B) 0.8 C) 0.4 D) 0.6


    2. Relevant equations
    fnet = f - umg = ma1 1st case
    Fnet = F - umg = ma2 2nd case

    3. The attempt at a solution
    I tried to solve it but u comes out to be zero.
     
  2. jcsd
  3. Dec 12, 2011 #2

    Doc Al

    User Avatar

    Staff: Mentor

    This looks good. (How do f and F relate?)

    Try it one more time.
     
  4. Dec 12, 2011 #3

    thanks! got the answer!
     
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