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Finding the Coefficiant of friction

  1. Nov 16, 2009 #1
    A cart that weighs 1.5 kg is accelerating at .12 M/s^2 on a horizontal surface. The cart is being pulled by a weight of 50 grams. Find the coefficiant of friction.

    I've been using F=ma so 1.5(.12)=.18N

    the weight pulling is equal to .05kg(9.8)=.49N

    .49-.18=.31N=Ff Ff=m(Fn) .31=m(1500) m (the coefficient of friction)= .0002

    I dont feel like this is the right answer, can anyone see what I'm doing wrong?
  2. jcsd
  3. Nov 16, 2009 #2
    Check your calculation for the normal force...Where did you get 1500 from?
  4. Nov 16, 2009 #3
    I thought in Normal force was measured in grams, not kilograms. That may be where I went wrong. So the proper equation should be .31/1.5=.2? That seems pretty simple and for some reason feel like I've messed up somewhere else but if that's all that I seem to have done wrong then thanks!
  5. Nov 16, 2009 #4
    Again make sure all your calculations are correct...If the Ff = .31 N and the mass of the object is 1.5 kg use the equation µmg=Ff to solve for µ. I think you understand the concepts, just make sure you are doing the algebra correctly...
  6. Nov 17, 2009 #5


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    Forces are measured in Newtons. Grams and kilograms are used for mass, not force.
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