The Coriolis force

At the quasi-scientific forums, with awkward periodicity, serious debates are raging about what is the Coriolis force and what are its apparent manifestations. Despite the venerable age of discovery - the phenomenon was described back in 1833 - some people are sometimes confused in the conclusions. For example, since Coriolis forces are most often associated with phenomena in the oceans and the atmosphere, on the Internet, one can come across the statement according to which the erosion of the banks of the rivers of the Northern Hemisphere occurs from the right side, while in the Southern the erosive effect of water appears mainly on the left banks. Some argue that this phenomenon creates the power of Coriolis. Their opponents explain everything differently: because of the rotation of the planet, the solid surface moves a little faster (less inertially) than the mass of water, and because of this difference, a washout occurs. Although in some part of the processes occurring in the ocean, the Coriolis force is indeed "guilty". The difficulty in determining it from a complex of other influences. Coriolis manifestation, like the force of gravitational interaction, is potentially.

Let's determine what kind of power and why it is of such interest. Since our planet can be considered a non-inertial system (moving and rotating), then any process considered relative to it should take into account inertia. Usually, to clarify this use a special pendulum longer than 50 m and weighing tens of kilograms. In addition, with respect to the motionless observer standing on the floor, the plane in which the pendulum swings rotates along the circumference. If the value of the speed of rotation of the planet is higher than the period of oscillation of the pendulum, then its conditional plane will shift toward the Northern Hemisphere, rotating in the opposite direction, relative to the clock. The converse is also true: increasing the period is higher than the Earth's rotation speed, it will lead to a shift in the direction of the hour hands. This is due to the fact that the rotation of the planet creates a pendulum acceleration in the pendulum system, the vector of which displaces the rolling plane.

For an explanation, you can take an example from life. For sure, everyone, being a child, rode on the carousel, which is a large disk rotating at some angular speed . Imagine two points on such a disk: one near the central axis (A), and the second - on the radius close to the edge (B). If the person at point A decides to move to point B, then, at first glance, the most optimal trajectory of motion will be a straight line AB, in fact, which is the radius of the disk. But with each step of the person, point B is shifted, since the disk continues to rotate. As a result, if we continue to move along the planned line-radius, then when the radius of point B is reached, it will no longer be there because of the displacement. If a person adjusts his path in accordance with the actual position of B, then the trajectory will represent a curved line, a wave whose vertex will be directed against the direction of rotation. However, there is a way to go from A to B along a straight line: this requires increasing the speed of movement by telling the body (person) acceleration. With increasing distance AB in order to maintain rectilinear motion , an ever increasing impulse of speed is needed. The difference between the described force and the centrifugal force is that the direction of the latter is the same as the radius on the rotating circle.

Thus, the Coriolis force exerts an effect on the motion of the rotating object. Its formula is as follows:

F = 2 * v * m * cosFi,

Where m is the mass of the moving body; V - speed of movement; CosFi is a quantity that takes into account the angle between the direction of motion and the axis of rotation.

Or, in vector representation:

F = - m * a,

Where a is the Coriolis acceleration. The sign "-" arises because the force from the side of the moving body is opposite to the direction.