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Homework Help: Force of Friction

  1. Jan 23, 2010 #1
    A force of 1.2N is applied to an object of mass 1.5Kg. It accelerates at 0.50 m/s^2. Determine the Force of friction and the Coefficient of Friction

    This is what I did. However, it seems that the Force of Friction is really low so I'm not sure if I did this question right.
    F=M * A ..which is can also be used as Fnet
    .:. Fnet= 1.5kg(0.50 m/s^2)
    = 0.75 N

    Fapp= 1.2 N

    Fnet=Fapplied + Ffriction
    Ffriction = Fnet-Fapplied
    = 0.75n -1.2 n
    = - 0.45 N


    If I continue to Figure out the coefficient of Friction it seems very unreasonable.

    Ffriction/ Fnormal = kinetic Coefficient

    -.45n/ -9.8m/s^2 * 1.5kg
    = .0382



    This may be right but I'm not quite sure. Any input would be great.
     
  2. jcsd
  3. Jan 24, 2010 #2

    kuruman

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    Draw a free body diagram. Say the applied force is to the right. Then the force of friction must be to the left. So from the FBD you get

    Fnet=Fapplied - Ffriction, not what you have.
     
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