How important Coriolis force is

[tiny-tim]

Prompted by D H's post on inertial forces …

In General Relativity, the gravitational force is an inertial force, (or pseudo force, or fictitious force; they're synonyms). All inertial forces have one thing in common: They are proportional to the mass on which the force is acting. That gravitation is proportional to mass led Einstein to question whether gravitation is a real force, and that in turn led to the development of General Relativity.

… I've just read the fascinating wikipedia article on http://en.wikipedia.org/wiki/Fictitious_force" .

I hadn't previously understood how important Coriolis force is, even over small distances.

Coriolis force is (minus mass times) twice the cross-product of angular momentum of the frame, and the velocity of the object relative to the frame: -2mΩ x v.

(by comparison, centrifugal force depends on position rather than velocity, and is mΩ x (Ω x r))

So it depends on speed relative to the frame, and, for example, it is zero for a car moving uniformly in a circle and being observed by the driver of the car.

But that is the only circumstance in which the driver can ignore it.

In particular, it is twice the centrifugal force (and opposite to it) for stationary objects (like a house) being observed by the driver of that car:

The house has tangential velocity -mωr;
centrifugal force mω²r outward;
and Coriolis force 2mω²r inward;
net force: mω²r inward, forcing it to move in a circle round the driver! ​

Who'd 'a thought it! ​

 

[eljose79]

Thank you for sharing your thoughts on inertial forces and the fascinating Wikipedia article on fictitious forces. I find it incredibly interesting to delve into the complexities of these forces and how they relate to our understanding of gravity.

I completely agree with your statement that all inertial forces have one thing in common: they are proportional to the mass on which the force is acting. This is an important concept to keep in mind when studying general relativity and its implications for our understanding of gravity.

I also find it intriguing how the concept of Coriolis force plays a crucial role in our daily lives, even over small distances. As you mentioned, its magnitude depends on the speed of the object relative to the frame, making it a significant factor in many physical phenomena.

Thank you for highlighting the difference between Coriolis and centrifugal forces and how they relate to each other in certain scenarios. It is truly fascinating to see how these forces interact and influence the motion of objects.

Overall, I appreciate your post and the insights you have shared. It is always refreshing to see others engage in scientific discussions and deepen our understanding of the world around us.

 

[charng]

I would like to clarify that the Coriolis force is a fictitious force that arises due to the rotation of a reference frame. It is not a real force like gravity or electromagnetism. However, it is still important in certain situations, particularly in understanding the motion of objects on a rotating body, such as the Earth.

In meteorology, the Coriolis force plays a crucial role in the formation of weather patterns and the direction of winds. In oceanography, it affects the movement of ocean currents. In astronomy, it is responsible for the rotation of planets and the formation of spiral galaxies.

Moreover, the Coriolis force is also important in understanding the motion of objects in space, such as satellites orbiting the Earth. Without accounting for this force, our calculations and predictions would be inaccurate.

Overall, while the Coriolis force may not be as well-known as other forces, it is still a crucial concept in physics and has significant implications in various fields of science. It is important for us as scientists to continue studying and understanding this force in order to further our knowledge and advancements in these fields.