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Circular motion lab problem

  1. Oct 28, 2012 #1
    1. The problem statement, all variables and given/known data
    For a conical pendulum:

    Construct a free-body diagram for the pendulum and derive an expression for the acceleration in terms of the gravitational field strength g, the length L of the pendulum, the radius r of the circular path of the pendulum, and the frequency f of oscillation. (Hint - first derive an expression for tanθ the angle between the string and the vertical.)
    images?q=tbn:ANd9GcQfoD9buysmpjtMKI8izKhqaemIS1HEzbEyXfKONl99Y2lQ69A3LERCiGYHOQ.png

    2. Relevant equations
    a=v^2/r
    a=Δv/Δt
    a=ƩF/m

    3. The attempt at a solution
    Have done free body diagram, can't figure out how to make equation.
     
    Last edited: Oct 28, 2012
  2. jcsd
  3. Oct 28, 2012 #2

    haruspex

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    There is a specific format you are supposed to use on this forum.
    What do you have for the forces - just describe them, don't worry about a diagram.
    What do you have for the acceleration?
     
  4. Oct 28, 2012 #3
    Thank you for replying; didn't see I had to use that form.
    As for forces there is the force of gravity on the pendulum mass (downwards), and the tension in the string.
    As for the acceleration - I have no numerical value for it. The question needs no actual values - just variables to make the equation (a in terms of g, L, r, and f).
     
  5. Oct 28, 2012 #4

    haruspex

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    True, but you do know the direction the acceleration has to be in. So in what directions would you resolve the forces, and what equations result?
     
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