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Homework Help: Acceleration of system.

  1. Oct 6, 2013 #1
    General question.

    1. The problem statement, all variables and given/known data

    you are given theta, μ, and both masses. Find the acceleration of the system so the block does not slip.

    3. The attempt at a solution

    Let m1 be the block, and m2 be the trapezoid car thing.
    Let F be the applied force
    I used a coord system with the x axis along the area where the trapezoid touches the block. I came up with:

    Fnet = m1 g sin θ - ff

    Fnet = m1 g sin θ - u F sin theta - u m1 g cos theta = 0

    Substituting for the system gives:

    [tex] a = \frac{ -\mu_k m_1 g \cos\theta + m_1g\sin\theta }{\mu_k sin\theta (m_1+m_2) } [/tex]

    Although i think this is incorrect since i did not account for the normal force of the car onto the block. Can someone correct this?

    Attached Files:

  2. jcsd
  3. Oct 6, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper

    Please show your reasoning. I can see what ##\theta## and ##\mu## are, but which mass is ##m_1## and which ##m_2##? What does "ff" mean in your equations?

    Since this is homework, we won't correct it for you.
    What we can do is help you correct it for yourself.
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