I have read that the Coriolis force is a psuedo force in a rotating system. But what is the origin and direction of this force? I searched in Wikipedia but it didn't help me much. So I need a intuition about what causes this force.
Please discuss with examples and with images.
You're on a merry-go-round and you walk out radially toward the edge. The circumferential velocity of the merry-go-round increases with radius, right ($\omega r$)? So as you walk out radially, your velocity in the circumferential direction must be increasing. The merry-go-round supplies the required frictional force on your foot to bring about this circumferential acceleration. This is called the Coriolis force.
Also, if you are walking circumferentially relative to the already-rotating merry-go-round platform, your tangential velocity becomes higher than the local platform tangential velocity. This requires additional force in the radial direction to keep you moving in a circle. So your radial acceleration has increased merely by walking tangentially. The merry-go-round supplies the required frictional force on your foot to bring about this additional radial acceleration. This too is called the Coriolis force.
So, basically, any time you walk at a constant velocity in any arbitrary direction on the platform, the platform must supply a frictional force on your foot perpendicular to the direction that you're walking (to allow this movement to occur). We call this a Coriolis force.
You’re on a train at the Equator heading North. As you travel, your velocity vector flattens out from originally pointing “up” (as you look at a globe). That’s natural, as the Earth produces a gravitational force.
But if the Earth also rotates 90 degrees in the time it takes your train to get to the North Pole, then your final velocity vector at the pole points “left” for some reason (again, looking at a globe). What could have caused this vector rotation? The Coriolis force.
