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Homework Help: A fun new circular motion question!

  1. Sep 17, 2008 #1
    16a483k.png

    Ok, so I set 9.8=v^2/r , therefore v=[tex]\sqrt{9.8r}[/tex]. I converted r from miles into meters and got 3459.35. This seems like an easy enough question, but for some reason I keep getting it wrong. The answer I keep getting is 184.12395m/s, but the question asks for it in rad/s. I've looked everywhere on how to convert m/s to rad/s, but no luck. I don't know if the problem is the conversion or my method in attaining v. Also is v=angular speed? Thanks in advance to all you physics geniuses out there.
     
  2. jcsd
  3. Sep 17, 2008 #2
    BUMP for help please.
     
  4. Sep 17, 2008 #3

    Dick

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    v is linear speed in m/s. The angular speed in radians/s=v/r.
     
  5. Sep 17, 2008 #4
    So what you're saying is that I set 9.8=v/(radius of cylinder) ?

    (3459.35)(9.8)=v

    33901.73=v=angular speed in rad/s

    Is this correct?
     
  6. Sep 17, 2008 #5

    Dick

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    No, no, no. You found v. The angular velocity is v/r.
     
  7. Sep 17, 2008 #6
    Could you define r?
     
  8. Sep 17, 2008 #7
    Radius :)

    2.15 mi.
     
    Last edited: Sep 17, 2008
  9. Sep 17, 2008 #8

    Dick

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    The same r you used in v^2/r. It's your notation.
     
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