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Acceleration directions and friction.

  1. Mar 2, 2013 #1
    Ok, I am analysing the situation in the attached image, and I am trying to find the frictional force between the nylon string and the top of the piping, but I am not sure what the value of acceleration will be. I understand how to do this when there is only acceleration due to gravity, but with this, centripetal acceleration is involved. Do I need to use vector resolution and find the total acceleration?

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    Last edited: Mar 2, 2013
  2. jcsd
  3. Mar 2, 2013 #2

    Ok, its very easy. Use total acceleration
  4. Mar 2, 2013 #3
    What are the forces acting on the system?
  5. Mar 2, 2013 #4
    Only gravity, and then also centripetal force once the rubber stopper begins spinning. But there is also the friction between the string and the pipe
  6. Mar 2, 2013 #5


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    Compared to the other forces involved, that friction is negligible.
  7. Mar 2, 2013 #6
    Yes, we also thought so, but we ran an experiment, and we found after comparing our results to what the values really should be using v = √(Fr/m), our values seemed to increase more so than the true values, so we believe that the additional frictional force is contributing and increasing the speed.
  8. Mar 2, 2013 #7


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    Was your piping a glass tube with the ends rounded by heating?

    How were you measuring V. Why not start with 4∏2rm / T2 rather than mv2/r - as it is easier to measure the Period.
  9. Mar 2, 2013 #8


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    Pls explain more about the experimental procedure, what was measured, and the results.
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