Centrifugal?

[joe1]

What is the difference between centrifugal force and centripetal force?
thanks

[jd_1984]

Centripetal force is directed toward the center of rotation of an orbiting body or object following a curved path. Centrifugal force is the apparent force, equal and opposite to the centripetal force, drawing a rotating body away from the center of rotation, caused by the inertia of the body.

Whenever you see a moving object that's not traveling in a straight line, you know that a force is acting upon it. That's because objects tend to resist changes to their velocities. The greater the mass, the greater the resistance to changes in velocity. That's called inertia. Objects at rest tend to stay at rest, and objects in motion tend to stay in motion, unless acted upon by some external force. (See Newton's First Law.)

Since velocity is a vector -- remember vectors have magnitude AND direction -- any change in an object's direction constitutes a changes in its velocity. When an object is flying around in a circle, its velocity is constantly changing because its direction is constantly changing! That means a force is working on it. That force is the centripetal force, and since force is equal to mass times acceleration, there must be an acceleration involved. You guessed it -- centripetal acceleration.

Imagine this...

There is a girl on a bike with a jump rope. Her spinning the bike pedals in centripetal force, though her spinning the jump rope around her is centrifugal force. The pedals are designed to keep the motion contained in a small area, keepiing the girl's feet right where they are, but the jump rope lashes out, with the chance of the girl losing her grip on it, due to its force.

Centripetal Force is more directed towards the center of the axis of rotation of an object following an elliptical or circular path. Centrifugal Force is the force that pulls away from the center because of the objects inertia.

Example: If you took a rock, tied it to a string, and swung it around, the forc

[jd_1984]

P.S - Not my words! But seemed like a far more complete answer than I could ever give

[DTCwordfan]

Centripetal force is a force that makes a body follow a curved path: it is always directed orthogonal to the velocity of the body, toward the instantaneous center of curvature of the path whereas Centrifugal force is the force that represents the effects of inertia that arise in connection with rotation and which are experienced as an outward force away from the center of rotation.

[jd_1984]

continued.........the force from the center of the axis of rotation is centripetal force. The force that causes the rock to pull away from the center, is centrifugal force. If you have ever been in a fast moving car that sharply turns and you feel as if you are pulled to the side, that too is centrifugal force caused by your inertia. The more mass the more inertia.

[factorfiction]

I'm sure that my 'A' level Physics teacher always insisted that there was no such thing as centrifugal force.

[naomi24]

^^ That rings a bell with me too.

[New Judge]

And he was absolutely right.This article:

http://www.regentspre.../bcentrif/centrif.htm

Explains it much better than I can.

[beso]

There is a common myth that centrifugal force does not exist. It is all about point of view.

While it does not exist in an inertial frame of reference it is a valid force in a rotating frame of reference.

[Hopkirk]

My A level physics teacher also told me there is no such thing as centrifugal force - he said it is actually a lack of centripetal force.

I didn't understand his explanation, but that wasn't unusual.

[beso]

Centrifugal force is not a lack of centripetal force. Centripetal force does not exist in the rotating frame of reference. To the moving body there appears to be an outward force. For example in the Graviton ride where the rider is pressed against the inside of the spinning body.

The centrifugal force in the rotating frame is equal and opposite to the centripetal force in the inertial frame.

[R1Geezer]

Centrpetal force has been describedadequately above. Centrefugal force is often described as a non force as it is really an effect of the fact that left to it's own devices a moving object will proceed in a straight line. So take one of those toy planes in the end of a string, when whizzed about the head "centrfugal" force keep the string taut, this is caused by the plane continuallly wanting to leave on a tangent but being pulled around. Ditto one of those Centrefuge devices for testing pilots etc, same thing.

[R1Geezer]

So "centrfugal force" is the name we give to arresting Newtons first law.

[chakka35]

New Judge's link explains it exactly as my Sixth Form Physics master did many years ago. It made sense then and it makes sense now.
What some attribute to a fictional centrifugal force is merely an object's normal behaviour when no centripetal force is applied to it.

[beso]

Occupants in the little aeroplane experience a centrifugal force because their frame of reference is the plane. It is the rotational frame view of the centripetal force in the inertial frame.

Those in the inertial frame of reference (on the ground) see a string held taut by the hand that holds it at the centre applying a centripetal force to the aeroplane.

The centripetal force forces the plane into a circle away from its inertial path.

The adjective "fictional" is not appropriate as applied to centrifugal force because frame of reference is a real parameter in any observation. Einstein showed that Gravitation is entirely indistinguishable from an accelerated frame of reference suggesting that it is indeed the result of an accelerated frame. This does not make gravity a fictional force, rather a result of the frame we use to observe reality.

This is what Relativity is about. Moving relative to something changes the perception especially when the speed becomes large.

[Hopkirk]

No, sorry. Way over my head.

[mibn2cweus]

It's important to understand that centrifugal force is not an external force acting upon a body but is an equal and opposite force inherent in a bodies reluctance to being pulled or accelerated away from a constant velocity of forward motion.

What is unique about gravity, when it is the centripetal force drawing a body away from an otherwise straight line trajectory, is that no inward acceleration nor outward force is felt by the effected body except for the stretching due to the varying strength of the gravitational field across the body along the line extending through their respective centres of gravity.
In the case of gravity, the attraction is mutual. The mass and velocity of a body through a gravitational field virtually redefine the geometry of a 'straight line'.

[R1Geezer]

pretty much everyting is over your head Hopkirk, I recommend chatterbank!