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Homework Help: Calculate the Frictional Force with Force, Mass, and Acceleration given.

  1. Sep 28, 2012 #1
    1. The problem statement, all variables and given/known data
    You apply a 2 Newton force to a 0.5 kilogram cart on a track and measure the acceleration of the cart with a motion detector. The acceleration is measured t be equal to 3.5 meters/sec2. Calculate the frictional force. In which direction compared to the applied force is it directed?

    2. Relevant equations
    The only equations I can think of are F=ma and f=μN.

    3. The attempt at a solution
    I have no idea where to start. Whenever I was given a problem in which I had to find acceleration, it was on a plane where I had angles and such to help me tie formulas together. have no clue what formula to use on this problem.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Sep 28, 2012 #2


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    Kristenx2: Welcome to PF!

    The cart i guess is assumed to be on a level horizontal track,and it is assumed that you are applying a horizontal force of 2 N. Newton's 2nd law in the horizontal direction states that the Net force in the horizonatal direction is equal to ma. Solve for the net force, and since you know the applied force, you should be able to solve for the friction force (without need to find the friction coefficient), and its direction.
    Note that there is no acceleration in the vertical direction, and thus, no net force in the vertical direction.
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