Coriolis force - Question about sign

  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. A.T.

    A.T. 6,339
    Science Advisor
    Gold Member

    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. AlephZero

    AlephZero 7,244
    Science Advisor
    Homework Helper

    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. tiny-tim

    tiny-tim 26,016
    Science Advisor
    Homework Helper

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

    (btw, this is a duplicate thread to
  6. A.T.

    A.T. 6,339
    Science Advisor
    Gold Member

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