# The Naked Scientists Forum

### Author Topic: Is there a centrifugal force?  (Read 4589 times)

#### Geezer

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##### Is there a centrifugal force?
« on: 13/05/2010 00:52:24 »
A long time ago, I was taught that there is no such thing as centrifugal force, but there is such a thing as a centripetal force.

I still see a lot of references to centrifugal force. What happened? Did centrifugal force come back into vogue?

#### JP

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##### Is there a centrifugal force?
« Reply #1 on: 13/05/2010 02:07:50 »
There's still no such thing as a centrifugal force.  It's an artifact of choosing to measure things while you're accelerating so that you see "forces" which aren't really there.  It's still avoided in intro physics courses, because it's extremely confusing unless you have a good grasp of the basics.

Still, it can be a useful mathematical tool at times, as long as you realize you're not talking about a real, physical force.

#### lightarrow

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##### Is there a centrifugal force?
« Reply #2 on: 14/05/2010 01:27:03 »
A long time ago, I was taught that there is no such thing as centrifugal force, but there is such a thing as a centripetal force.

I still see a lot of references to centrifugal force. What happened? Did centrifugal force come back into vogue?
Centrifugal force is not a "real" force as JP wrote, because it's only due to the fact the frame of reference is accelerating. Nontheless it could be considered, *in an accelerating frame of reference only* and if you still want to use F = m•a.

Note that, in GR, the concept of centrifugal force and of inertial forces in general acquires a deeper meaning, since, because of equivalence principle, locally an inertial field is equivalent to a gravitational field.
« Last Edit: 14/05/2010 01:28:53 by lightarrow »

#### Bored chemist

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##### Is there a centrifugal force?
« Reply #3 on: 14/05/2010 18:40:10 »
I think it's probably sensible to accept a compromise. Centrifugal forces exist on Mondays through Wednesdays. They do not exist on Wednesday through to Saturday and nobody mentions them on Sundays because that's set aside as a day of rest.

#### rwjefferson

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##### Is there a centrifugal force?
« Reply #4 on: 15/05/2010 01:38:01 »
A long time ago, I was taught that there is no such thing as centrifugal force, but there is such a thing as a centripetal force.
I still see a lot of references to centrifugal force. What happened? Did centrifugal force come back into vogue?

There is one force in verse everything.  Centrifugal is just another Name for force in verse gravity.  Yes, inertial differential is the force that orbits satellites.  No, inertial deferential is not a new or outdated theory.  Neither is aether as a state of force.

rwjefferson

#### lightarrow

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##### Is there a centrifugal force?
« Reply #5 on: 15/05/2010 02:54:27 »
A long time ago, I was taught that there is no such thing as centrifugal force, but there is such a thing as a centripetal force.
I still see a lot of references to centrifugal force. What happened? Did centrifugal force come back into vogue?

There is one force in verse everything.  Centrifugal is just another Name for force in verse gravity.  Yes, inertial differential is the force that orbits satellites.  No, inertial deferential is not a new or outdated theory.  Neither is aether as a state of force.
Sorry but what you wrote is wrong. I have already explained why.

#### JP

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##### Is there a centrifugal force?
« Reply #6 on: 15/05/2010 03:42:18 »
There is one force in verse . . .

Gin a body meet a body
Flyin' through the air.
Gin a body hit a body,
Will it fly? And where?
Ilka impact has its measure,
Ne'er a ane hae I,
Yet a' the lads they measure me,
Or, at least, they try.

Gin a body meet a body
Altogether free,
How they travel afterwards
We do not always see.
Ilka problem has its method
By analytics high;
For me, I ken na ane o' them,
But what the waur am I?

James Clerk Maxwell
(http://www.haverford.edu/physics-astro/songs/rigid.htm)

#### rwjefferson

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##### Is there a centrifugal force?
« Reply #7 on: 15/05/2010 04:22:23 »
]Sorry but what you wrote is wrong. I have already explained why.

Please fell free re: resh my memory.  Please tell again how you might have all ready explained centripetal is not another Name of attractive energy.

ItS
peace
rwj~

#### Geezer

• Neilep Level Member
• Posts: 8328
• "Vive la résistance!"
##### Is there a centrifugal force?
« Reply #8 on: 15/05/2010 05:28:59 »

Gin a body meet a body
Flyin' through the air.
Gin a body hit a body,
Will it fly? And where?
Ilka impact has its measure,
Ne'er a ane hae I,
Yet a' the lads they measure me,
Or, at least, they try.

Gin a body meet a body
Altogether free,
How they travel afterwards
We do not always see.
Ilka problem has its method
By analytics high;
For me, I ken na ane o' them,
But what the waur am I?

James Clerk Maxwell
(http://www.haverford.edu/physics-astro/songs/rigid.htm)

I actually understand that one! Thanks JP.

#### lightarrow

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##### Is there a centrifugal force?
« Reply #9 on: 17/05/2010 20:03:19 »
]Sorry but what you wrote is wrong. I have already explained why.

Please fell free re: resh my memory.  Please tell again how you might have all ready explained centripetal is not another Name of attractive energy.
First, you made a lot of mistakes:
a. You didn't want to say "inverse", but "opposite".
b. A force is not an energy.
c. There is no principle wich states that for every force there is an opposite one acting on the same body, otherwise no body would ever accelerate.
d. If you intended to talk about the third principle of dynamics then you have to know that it's not always valid, for example in relativity (forces don't propagate at infinite speed).

That said, centrifugal force appears *only* in an accelerated frame of reference, as well as Coriolis force. In an inertial frame you have only 1 force: Earth's gravity acting on the satellite. In a frame of reference which rotates with the satellite, you have *3* forces on the satellite:

1. Earth's gravity
2. centrifugal force
3. Coriolis force.
« Last Edit: 17/05/2010 20:07:57 by lightarrow »

#### The Naked Scientists Forum

##### Is there a centrifugal force?
« Reply #9 on: 17/05/2010 20:03:19 »