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Homework Help: Physics Ramp Problem.

  1. May 5, 2009 #1
    1. The problem statement, all variables and given/known data
    A 2.0kg block of wood accelerates from rest down a smooth incline at 37o to the horizontal. It covers 1.26m in 1.0sec. Determine the frictional force acting.

    2. Relevant equations
    uhhh... this is the problem, I don't know what equation to use...

    3. The attempt at a solution
    can someone please help me?
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. May 5, 2009 #2
    Calculate the net accleration to get the net force, then subtract off the component of gravity that is pointing down the ramp. The remaining force is kinetic friction.
  4. May 6, 2009 #3


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    Homework Helper

    If I were doing this problem, I'd:

    1. Draw a free body diagram showing the ramp and forces acting on the block

    2. Write the equations of motion of the block (i.e. sum F = ma)

    3. Integrate twice to get an expression for x = x(t) where x is the distance the block travels down the ramp keeping in mind the initial conditions (hint: accelerates from rest)

    4. Since you are given the distance traveled in a specific time, equation (3) can be solved for the friction force
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