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Homework Help: Circular Motion Equation homework

  1. Jun 26, 2015 #1
    1. The problem statement, all variables and given/known data

    2. Relevant equations
    Circular Motion Equation

    3. The attempt at a solution
    I solved the problem and got the result to be 6 m/s2 but it is not one of the answers. I was pretty sure of my solution. So, are all choices wrong?

    F = ma
    mg sin 37 = ma
    a = g sin 37 = 6.01 m/s2
  2. jcsd
  3. Jun 26, 2015 #2


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    Homework Helper

    Yep I agree with you.
  4. Jun 27, 2015 #3

    rude man

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    Gold Member

    I got 5.9 ms-2 so same answer if g = 9.8 ms-2 instead of 10.
    BUT - I don't like your rationale.
    The force on the mass includes the tension from the string which you have ignored.
    I suggest instead τ = Id2θ/dt2
    I = mR2
    Answer is the same though.
    EDIT: on the other hand, maybe you were quick enough to realize that the tension vector, being orthogonal to the tangent vector, cannot impart force, therefore acceleration, in the tangential direction, making what you originally did 100% justified.
    Last edited: Jun 27, 2015
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