# What is Coriolis: Definition and 177 Discussions

In physics, the Coriolis force is an inertial or fictitious force that acts on objects that are in motion within a frame of reference that rotates with respect to an inertial frame. In a reference frame with clockwise rotation, the force acts to the left of the motion of the object. In one with anticlockwise (or counterclockwise) rotation, the force acts to the right. Deflection of an object due to the Coriolis force is called the Coriolis effect. Though recognized previously by others, the mathematical expression for the Coriolis force appeared in an 1835 paper by French scientist Gaspard-Gustave de Coriolis, in connection with the theory of water wheels. Early in the 20th century, the term Coriolis force began to be used in connection with meteorology.
Newton's laws of motion describe the motion of an object in an inertial (non-accelerating) frame of reference. When Newton's laws are transformed to a rotating frame of reference, the Coriolis and centrifugal accelerations appear. When applied to massive objects, the respective forces are proportional to the masses of them. The Coriolis force is proportional to the rotation rate and the centrifugal force is proportional to the square of the rotation rate. The Coriolis force acts in a direction perpendicular to the rotation axis and to the velocity of the body in the rotating frame and is proportional to the object's speed in the rotating frame (more precisely, to the component of its velocity that is perpendicular to the axis of rotation). The centrifugal force acts outwards in the radial direction and is proportional to the distance of the body from the axis of the rotating frame. These additional forces are termed inertial forces, fictitious forces or pseudo forces. By accounting for the rotation by addition of these fictitious forces, Newton's laws of motion can be applied to a rotating system as though it was an inertial system. They are correction factors which are not required in a non-rotating system.In popular (non-technical) usage of the term "Coriolis effect", the rotating reference frame implied is almost always the Earth. Because the Earth spins, Earth-bound observers need to account for the Coriolis force to correctly analyze the motion of objects. The Earth completes one rotation for each day/night cycle, so for motions of everyday objects the Coriolis force is usually quite small compared with other forces; its effects generally become noticeable only for motions occurring over large distances and long periods of time, such as large-scale movement of air in the atmosphere or water in the ocean; or where high precision is important, such as long-range artillery or missile trajectories. Such motions are constrained by the surface of the Earth, so only the horizontal component of the Coriolis force is generally important. This force causes moving objects on the surface of the Earth to be deflected to the right (with respect to the direction of travel) in the Northern Hemisphere and to the left in the Southern Hemisphere. The horizontal deflection effect is greater near the poles, since the effective rotation rate about a local vertical axis is largest there, and decreases to zero at the equator. Rather than flowing directly from areas of high pressure to low pressure, as they would in a non-rotating system, winds and currents tend to flow to the right of this direction north of the equator (anticlockwise) and to the left of this direction south of it (clockwise). This effect is responsible for the rotation and thus formation of cyclones (see Coriolis effects in meteorology).
For an intuitive explanation of the origin of the Coriolis force, consider an object, constrained to follow the Earth's surface and moving northward in the northern hemisphere. Viewed from outer space, the object does not appear to go due north, but has an eastward motion (it rotates around toward the right along with the surface of the Earth). The further north it travels, the smaller the "diameter of its parallel" (the minimum distance from the surface point to the axis of rotation, which is in a plane orthogonal to the axis), and so the slower the eastward motion of its surface. As the object moves north, to higher latitudes, it has a tendency to maintain the eastward speed it started with (rather than slowing down to match the reduced eastward speed of local objects on the Earth's surface), so it veers east (i.e. to the right of its initial motion).Though not obvious from this example, which considers northward motion, the horizontal deflection occurs equally for objects moving eastward or westward (or in any other direction). However, the theory that the effect determines the rotation of draining water in a typical size household bathtub, sink or toilet has been repeatedly disproven by modern-day scientists; the force is negligibly small compared to the many other influences on the rotation.

View More On Wikipedia.org
1. ### How Does Coriolis Force Influence Particle Motion in Rotating Systems?

Source : JEE Advanced , Physics Sir JEE YT I tried to attempt it using Lagrangian , so according to the coordinate axes given in the diagram , the position of the particle is let's say ##(0,d,-z)## Let ##r## be the distance between the particle and the axis of rotation such that it subtends...
2. ### I Coriolis effect and the acceleration experienced in a rotating frame

Is the reason behind coriolis acceleration is that as you move far from the centre of a rotating frame the tangential velocity increases?
3. ### I Exploring the Coriolis Force: Real or Imagined?

Is the Coriolis force actually experienced by an object, or is the object simply deflected in its path?

5. ### I Coriolis acceleration of a projectile launched at the equator

I have a question about the Coriolis acceleration experienced by a projectile launched from the surface of a rotating body. Say a ball is launched at 45 degree angle relative to the surface at some initial velocity v0. Let's further specify that the ball is launched due north from the equator...
6. ### Coriolis Force in East-West Direction

For objects traveling north or south, the Coriolis force makes sense. The velocity of the Earth's surface changes with latitude, causing an object to drift east or west relative to the Earth's surface. However, when an object is traveling east or west, the latitude is not changing. How would...
7. ### Understanding the Coriolis Force: How to Calculate It

I know that the perpendicular force is the Coriolis force, but I don't know how to get it
8. ### Coriolis effect and water experiment

Is the Uganda water experiment (that shows corilios effect on water drain) a scientific experiment or not? I searched but I couldn't find a final answer to this question. There are two opposite opinions, which one is correct? Or this argument is an open issue yet? Thanks for your replies...
9. ### Optical Compact Device For Measuring Speed of Light

Hi. This is an idea which I just happened to think of, and I was curious if it would be at all feasible. Here's a quick sketch I drew: The two curved mirrors should have a laser attached on one end and a video camera attached on the other. The laser would be tilted very slightly above...
10. ### Coriolis Force and Centrifugal Force

Hello! So for a) I have done the following m = 400t = 400000 kg v = 300 km/h = 83,3 m/s ##\alpha## = 50 (degrees) Now this is the formula for the Coriollis effect $$F = 2 \cdot m (v × \omega)$$ So in a book I found in the library regarding physics I've found a similar example that used...
11. ### Direction of the Coriolis force

How can I determine direction of Coriolis force for these cases?1)Ship travel at 45th north parallel to the east (course 90°)2)Ship travel at north hemisphere at course 45°3)Ship travel at equator at east (course 90°) My attempt: 1) Coriolis force is point up,vertical to the Earth surface 2)I...
12. ### Coriolis inertial acceleration

I am a self learner. I have a specific question regarding the Coriolis inertial acceleration. If question is already answered on this forum please redirect me there. As depicted on the picture we have rotating platform and the chain of particles passing across the rotating platform. The...
13. ### Rectilinear movement seen from a rotating reference frame

Let's suppose there's some platform that is rotating with angular speed omega and has a radius R. At t=0 we release some object from the border, which has an initial speed perpendicular to the radius direction with magnitude \omega R and we want to know its position at t=T with respect to the...
14. ### Is the Coriolis Effect Real? Exploring Motion in a Tossed Ball Video

Does ball (in video)when flying ,going in straight line or in curve line,so if I am inside this ball, will I feel like I am in car which accelarate in straight line or car which accelare in curve? I think ball is going straight,curved path is just illusion..
15. ### I The solar system and the Coriolis effect

After concluding an investigation about the coriolis effect, I wondered how this phenomenon affected the solar system and in particular the moon. Since the moon is a body that moves within the rotating system formed by the sun and the earth, an apparent deviation in the moon's path would be...
16. ### B Coriolis problem - Point mass movement upon release from Earth

If there was no atmosphere and a point mass was released at the 45th parallel and able to counteract the centripetal force of gravity (hovering 10ft off the surface), how long would it take before it ended up at the equator.
17. ### Which Way Will the Water Go?

In which Destin and Steve settle an argument with an amazing experiment.
18. ### Calculating Centrifugal & Coriolis Forces at Rest

so I can find the centrifugal force but shouldn't the Coriolis force be 0 because the mass is at rest?
19. ### Coriolis force caused by tangential velocity

From another recent thread I learned that you see a Coriolis force if an object in a rotating reference frame moves along a tangent at some velocity v. (I was already familiar with the case where the velocity is radial). I still find it a little counter-intuitive that the force has the same...
20. ### Does the Coriolis force act on the propagation of light?

Summary: Robert Sungenis explains the sagnac effect Robert Sungenis, a well-known proponent of geocentrism, has authored a https://gwwdvd.com/what-allows-the-sun-to-revolve-around-the-earth/ in which he tries to explain the Sagnac effect as a result of Coriolis force (p.16-17), which he thinks...
21. ### Coriolis and Centrifugal effects in balance

Hi all, Consider a platform with angular velocity ##\omega##. A particle on top of it has a velocity with only ##\hat \theta## component (no radial ##\hat r## velocity). In this case, the inertial forces read: $$F_{in} = 2m\omega V_\theta \, \hat r + m \omega^2 r \, \hat r$$ If ##V_\theta =...
22. ### How Does the Coriolis Force Affect Particle Motion in a Rotating System?

m = Particles mass, Omega = Systems angular frequency, v' = particles velocity. Attempt at a Solution: $$F_{C} = -2m \bar{\omega} \times \bar{v}^{'} = -2 \bar{\omega} \times \bar{p} = 2 \bar{p} \times \bar{\omega}$$ Let  \bar{\omega} = \frac {\bar{r} \times \bar{v}} {r^2}, \alpha = \frac...
23. ### I Coriolis force, real or just an illusion?

So does then huricans really rotate or just appear to rotate? Does wind particles in huricane feel centrifugal force because they move in curved path or maybe not because they actually go in straight line? I never understand coriolis force 100%,is wind particles really rotate or this is just...
24. ### I Fictitious forces -- name convention

Hello all, I understand there are four d'Alembert (fictitious) (non-inertial) forces: 1. Coriolis 2. Centrifugal 3. Linear 4. Angular acceleration. But then I think about the Gyroscopic Effect (I understand how it arises, so that is not the issue). I am wondering if one can "classify" these...
25. ### How is the Coriolis generalized potential obtained

The Coriolis potential last term of (42) is obtained by integration through r and R from last term of (40). I do not understand why we do not need to integrate through v as well, since the Coriolis force depends on v? Homework Equations Equation (41) is wrong I think, L must be replaced by...
26. ### Torque about center of mass due to Coriolis force, is it 0?

It’s essentially a question about cross product identities. I want to analyze a problem in a frame of reference which is rotating with angular velocity ##\vec \Omega## relative to an inertial frame. In this non-inertial frame, we have a rigid body rotating with constant angular velocity ##\vec...
27. ### Coriolis force and the Earth's rotation

Homework Statement A body is thrown as shown in the picture (0°<x<90°). In what direction the body will the body move in relation to the point it was thrown from - east or west (assume the distance between the point the body was thrown from and the point it lands at is no more than a few...
28. ### Deriving Ball Movement on Northern Hemisphere with Rotating Reference Frame

I have a ball of mass m that is situated on horizontal plane on the northern Hampshire. I am asked to show that the ball is moving, clockwise, in a manner of r = v / ( 2Ω*sin(λ) ) where v is the ball's velocity, Ω is Earth's angular velocity, and λ is the terrestrial latitude So here's what...
29. ### I Conceptual question about the Coriolis force and the weather

Dear all, there is something bugging me for a while now, and it's about a favourite topic of confusion: the Coriolis-force! A fictitious force is a force which disappears if you transform to an inertial frame. At the algebraic level I have a good understanding of this, I think (Newton's 2nd...
30. ### Problem with Coriolis Acceleration

Homework Statement Find the magnitude in g's of the Coriolis acceleration due to the Earth's rotation of a plane flying 600 mph due north over the location of latitude (37˚13'04"N), longitude (121˚50'39"W), at an elevation of 80 meters above mean sea level. Homework Equations aCor = 2Ω × vxy...
31. ### Coriolis Drift of Discrete Objects

I am writing a program aimed at 'gun nuts' designed to display Coriolis Drift of bullets (ie, 'discrete objects in free-fall', and not large fluid masses). Using the 2 equations below, I am able to calculate and display the values of Coriolis Drift (in terms of X & Y (vertical and horizontal))...
32. ### Dynamic reaction versus Coriolis acceleration of the disk

<< Thread moved from the technical forums, so no Homework Help Template is shown >> I have mind boggling problem, trying to distinguish between Dynamic reaction versus Coriolis acceleration of thin hoop. Problem: A thin, hoop of mass m and radius r spins at the constant rate ω 1 about an axle...
33. ### I On the Coriolis Forcing vector and its Matrix

The context for the question is in the attachments (pg1.png, pg2.png, pg3.png), so there is some reading involved. Although, it is a short and simple read if anything. The inquiry is in (inquiry.png). My understanding of the situation is that Q(t) abides by the differential equation Q'(t)Q(t)T...
34. ### I Space elevator and Coriolis force

It seems to me that the concept of a space elevator does not take Coriolis force into account. If the elevator were in built with a space station in geosynchronous orbit and counterweight then there is more to reaching the space station than just climbing the rope. The rope would have to be...
35. ### I How to derive Coriolis acceleration from Frénet–Serret?

I've been able to derive the centripetal & transverse accelerations, and I understand how the radius of curvature is the reciprocal of the curvature, and that to get the radial & Coriolis acceleration, I need to get the time derivatives of the radius of curvature, but I don't see exactly how...
36. ### Question about the Coriolis effect

Homework Statement It's a question about the deviation of a bullet fired on Earth's surface: **I solved the question, but I can't figure out what exactly this deviation means, where is it on the following question's picture: The problem: A bullet is fired from a gun towards a target at...
37. ### Coriolis effect example: ball tossing on rotating carousel

Hi all, I was reviewing the Coriolis effect and I came across the attached explanatory image (from the Italian version of a book on physics by Cutnell, Johnson, Young and Stadler). The idea is the following. two guys are facing each other on a rotating carousel; one of the guys on the throws...
38. ### The Coriolis Force: Where Will It Take You?

Homework Statement A plane is flying in latitude 25S to the west. due to the Coriolis force will he fly to the southern pole or to the equator? and the same question but that he is flying to the west in 25N? Homework EquationsThe Attempt at a Solution I'm not sure, but think that Coriolis...
39. A

### How Calculate Coriolis aceleration from Christoffel Symbols?

Homework Statement Hi, We are trying to calculate the Coriolis acceleration from the Cristoffel symbols in spherical coordinates for the flat space. I think this problem is interesting because, maybe it's a good way if we want to do the calculations with a computer. We start whit the...
40. ### Coriolis effect on ballistics and old chart

Hello, I was looking through an old Naval gunnery guide that tabulates deflections due to the Coriolis effect. I must be reading this wrong or I don't understand how they are reckoning direction. If I am at the equator and I shoot north, shouldn't the bullet deflect the the right of the...
41. ### Coriolis effect, Conservation of Angular Momentium, Planes

I have a couple of questions that i thougth this group could help me with. 1. A plane (SR71) takes off from the equator, with a lateral speed, relative to space of 1000mph. (earth rotational speed) say it takes an hour to get there so, its going 10,000mph or something. . Tt flys over the...
42. ### Transforming to a Rotating Reference Frame

Homework Statement Let ## \mathbf{r} ## be the position of a point in a rigid body relative to some origin ##O##. Let ##\mathbf{R}## be the position of the centre of mass from that origin. ##\mathbf{r^{*}} = (\mathbf{r}-\mathbf{R})##. ## d\boldsymbol{\phi} ## is the infitesimal vector directed...
43. ### B What Causes a Particle to Move in a Circular Trajectory Due to Coriolis Force?

Hello, I got a question about the coriolis force. It is probably super simple, but I am still not getting it: The coriolis force, forces my particle onto a circle trajectory, but I am not sure why (yes, I can show it mathematically, but I want to understand what is happening). When I am moving a...
44. ### I Consider Coriolis force or not?

Hello, my question is very short. I have a spinning bar, with a small ring threaded. I know that for analyzing the problem I have to consider the centrifugal force that makes the small ring go away from the center. My question is do I have to also consider the coriolis force? : - 2m (w x v'), or...
45. ### Coriolis Force on a Race Car at 45 Degrees North

Homework Statement Find the magnitude and direction of the Coriolis force on a racing car of mass 10 metric tons traveling due south at a speed of 400km/hr at a lattitude of 45 degrees north. Homework Equations F_{cor}=-2m\omega\times v The Attempt at a Solution \omega=2\pi/(24*3600 \quad...
46. ### Angular momentum is conserved, but KE is not. How to find out why?

This (photo) is a very typical example of conservation of angular momentum, but my trouble arrises from trying to prove that the difference of energy will have to correspond to work, by calculating the work done by you to alter the moment of inertia. I have spent a lot of time in this, but I...
47. ### I Reconciling the Coriolis Force Contradiction on a Spinning Disk

Imagine there is a frictionless disk that spins with angular speed w. There is a ball on it that sits motionless at some radius r from the center. Now, switch to the frame of the rotating disk. In this frame the ball should be spinning with speed w * r. Edit: To be clear, the ball is NOT moving...
48. ### Understanding Coriolis Force in a Rotating Pipe

Homework Statement Homework Equations https://wikimedia.org/api/rest_v1/media/math/render/svg/1a061d2667e5d9f69dc385e359e7260a3eb1deff https://wikimedia.org/api/rest_v1/media/math/render/svg/ba88069934aa8abb2a2466f84121f385e6e8971f The Attempt at a Solution I have solved equation for r(t) and...
49. ### I Unraveling the Confusion: Coriolis Effect on a Frictionless Air-Hockey Earth

If Earth was turned into an air-hockey planet, with no friction (or air friction), and I was in New York and I shoved an air hockey puck North, would the hockey puck trace out the same sinusoidal-type path that a satellite/space station does (spending an equal amount of time in the northern and...
50. ### Coriolis Force Across the Equator

Homework Statement A fast sprinter with a mass of 80 kg runs across the equator. What is the value of the Coriolis force he experiences? Homework Equations F=ma a=2ωVradial ω=7.27 x10-5 rads-1 Earth rotates from west to east. The Attempt at a Solution I pick a direction of travel - South to...