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Homework Help: I need help with Radial Acceleration -it is an easy one

  1. Nov 28, 2011 #1
    The period of the rotation of an airplanes ellipse is T=3 milliseconds,linear speed in the top is 3*10^3 m/s.What's the centripetal(radial) acceleration of the top?I need a step by step guide it would be really helpful.Thanks.
     
  2. jcsd
  3. Nov 28, 2011 #2
  4. Nov 28, 2011 #3
    If I knew what an 'airplane ellipse' is, I could probably help you.
     
  5. Nov 29, 2011 #4
    Sorry I meant an airplanes propeller.
     
  6. Nov 29, 2011 #5
    As physicsvalk kindly stated, show your previous working or attempts, we're here to help, not do it for you.
     
  7. Nov 29, 2011 #6
    Ok I did it.

    v=3000 m/s
    T=0.003s

    v=s/t 3000m/s = s / 0.003s s=vt s=3000m/s * 0.003s s=9m

    s=2piR 9m=2*3.14*R r=9m/6.28 r=1.432m

    a=v^2/r a=(3000m/s)^2 / 1.432m = 6.284916m/s^2
     
  8. Nov 29, 2011 #7

    BruceW

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    Yep, you got the same answer as I did. Your working is a little difficult to follow though.
     
  9. Nov 29, 2011 #8

    BruceW

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    Woops, no wait. Its wrong, because I made the same mistake you did. Its an order of magnitude mistake. (The numbers are right, but the decimal place is wrong).

    Maybe try again? I think you will get it right second time, since it is only the decimal place that is wrong, you must have been close, but maybe made a silly error?
     
  10. Nov 29, 2011 #9

    BruceW

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    In fact, I think it is just on the last line where you went wrong.
     
  11. Nov 29, 2011 #10
    yes it should have been 6284916m/s^2.Thanks to all for helping
     
  12. Nov 29, 2011 #11

    BruceW

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    yep, no worries
     
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