Quote by Curious2013
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?

You can swap
ω and
v, and the minus sign is gone:
2
ω x
v = 2
v x
ω
Quote by Curious2013
As far as I understand, it depends on what reference frame I use (inertial or non inertial

The Coriolis force exist only in non inertial frames.