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Coriolis force - Question about sign

  1. Dec 17, 2012 #1
    Dear all

    I have a question concerning the Coriolis acceleration expression. I learnt it as Ac = -2ω x v, where ω is the vector which indicates the rotation axis direction of Earth and v the velocity of a body that I want to check the Coriolis effect on.

    My question: where the minus sign comes from? As far as I understand, it depends on what reference frame I use (inertial or non inertial - the minus comes from the latter, like the Earth, in my conception). Am I correct?

    Thanks in advance!
     
  2. jcsd
  3. Dec 17, 2012 #2

    A.T.

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    You can swap ω and v, and the minus sign is gone:

    -2ω x v = 2v x ω

    The Coriolis force exist only in non inertial frames.
     
  4. Dec 17, 2012 #3

    AlephZero

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    The minus sign is there because humans made the arbitrary decision to use right-handed coordinate systems rather than left handed ones.

    The Coriolis force is just a consequece of Newton's laws of motion. The physics doesn't depend on what frame you use to describe it, or whether the frame is inertial or non-inertial. The details of the math depend on those things, but "the map is not the country", and similarly "the math is not the phyiscs".
     
  5. Dec 17, 2012 #4

    tiny-tim

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    no, it would still be there, because you'd still need v = ω x r :wink:

    (btw, this is a duplicate thread to https://www.physicsforums.com/showthread.php?t=659387)
     
  6. Dec 17, 2012 #5

    A.T.

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    To me it seems more like it's the arbitrary decision to have ω first in the term.
     
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