# Coriolis Force

1. Mar 22, 2003

### RuroumiKenshin

Does the Corioulis force effect our blood cycle[?]

2. Mar 23, 2003

### nbo10

It would but I doubt you would ever be able to measure it.

JMD

3. Mar 23, 2003

### damgo

Not noticeably.... you don't see significant effect from the Coriolis force except at very large scales, like with artillery shells. The maximum acceleration from Coriolis effects on the Earth is ~velocity/10,000 m/s^2, if that gives you an idea.

4. Mar 23, 2003

### RuroumiKenshin

Does the Coriolis force, in any way, pertain to the centrifugal force of the earth? Should "Coriolis" even be capitalized? If so, why?

5. Mar 23, 2003

### Zefram

It's capitalized because it was the guy's last name.

6. Mar 23, 2003

### Mulder

You get a Coriolis acceleration in addition to Centrifugal for example on a plane flying round the Earth - that is when you have something moving inside a rotating frame. For the 'person on the equator' example, only a centrifugal acceleration is acting because he's standing still. If that's what you're asking? Happy to try to explain better/further if you want...

7. Mar 24, 2003

Staff Emeritus
The Coriolis force tends to turn a vector clockwise in the Northern hemisphere and counterclockwise in the Southern hemisphere, with a force proportional to the sine of the latitude. So it is zero at the equator, where latitude is 0o, because sine 0o = 0. And it is maximum at the poles, where latitude is 90o mbecause the sine function has its maximum there, where sine 90o = 1. At the poles the rate is (duh) 360o per 24 hours or 15o per hour.

8. Mar 24, 2003

### RuroumiKenshin

The plane you described, how exactly is it effected by the Coriolis force? (I know it's experiencing free fall)

9. Mar 24, 2003

### Mulder

Some of this you may understand.

The Coriolis force acts at a right angle to the plane's velocity and the Earth's angular velocity. The right hand rule can be used to work out exactly which direction the force will be in - it depends on the direction of the plane. Just as an example, if a plane was in the Northern hemisphere, flying North, then the Coriolis force would act on the plane in a Easterly(!oops) direction (aswell as Centrifugal acting away from the surface of the Earth). You will probably need some understanding of the basics of vectors to fully know why, but just check out the link and then come back and ask more if you want

Last edited: Mar 24, 2003
10. Mar 24, 2003

### RuroumiKenshin

Is the "w" always defined as the wave front? I read in my book, "relativity beyond eintsien", that it is defined as the wave front relative to a newtonian co-ordinate system, K0.

11. Mar 25, 2003

### Mulder

The 'w' here in '-2mw x v' is the angular velocity of the Earth ie the Earths velocity / Earth radius, a constant 7.27e-05 radians per second. Forget relativity, this is good ole' Mechanics

12. Mar 25, 2003

### NEOclassic

Centrifugal force vis-a-vis Coreolis force!

Hi MV,

In Feynman notes Vol I Chapter 19 Richard points out that Centrifugal force is radial while Coriolis Force is tangential. In Chap 20 of Vol I he gets real when he reminds us that because angular momentum is a dipolar phenomenon, interaction with other dipoles demands vector cross-product, which gives perpendicular torque when the loop is inertial and perpendicular dipolar magnetism when the loop is electrostatic.
Most every High School Physics Lab has a bicycle wheel with a handle on each side of its axle. When you spin it and try to turn it, it tugs noticably to bend sidways toward the floor. Cheers, jim

13. Mar 25, 2003

### RuroumiKenshin

What does it mean by "Coriolis force is tangential"? My definition of tangent is a dent.

First off, I have zero knowledge of dipoles. I don't know anything about biophysics.

14. Mar 25, 2003

### RuroumiKenshin

How do you know when relativity is involved and when it isn't?

Also, isn't K0 Newtonian mechanics?

-2mw x v

so the -2 is multiplied by the mass, and then velocity/earth's radius? and then x, position and velocity are sort of left out, so what does that indicate?

15. Mar 25, 2003

### enigma

Staff Emeritus
A radian is a measurement of angle.

One radian is the distance around the circumference which is equal to the radius of the circle.

So if you have a circle of radius 2, start at one point on the circumference, and start walking, you will have travelled an angle of one radian when you have walked a distance of 2.

In the grand scheme of things, relativity is always involved. For most human sized problems (which means speeds up to the order of 10000s of km/hour, distances on the orders 10,000s of km), relativity can be completely ignored because it has such a tiny effect.

Last edited: Mar 25, 2003
16. Mar 25, 2003

### RuroumiKenshin

so the radius=radian?? Hmm...not from what I remember. So I must have misunderstood. Can you give me the formula? (it'd give me a better idea)

17. Mar 25, 2003

### NEOclassic

Hi again MV,
the radius of the circle is a "length", the arc of curved length subtending the angle identified as a radian has a length equal to one radius long. There are 2 x 3.14159-- radian angles in a full circle, and there are 2 x 3.14159- radius lengths in the circumference of the circle.
Cheers, Jim

18. Mar 25, 2003

### enigma

Staff Emeritus
Sorry, I must not have been too clear.

Cut out a 1 radian piece of a circle. Take the remaining piece of the circumference. If you stretch that arc out so it's straight, it will be the same length as the radius is.

19. Mar 26, 2003

### RuroumiKenshin

But there is a formula! Isn't it circumference/radius?

20. Mar 26, 2003

### enigma

Staff Emeritus
A formula for what?

There are 2*pi radians in a circle. The arclength of an arc subtended by an angle is equal to the angle in radians * the radius.