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Centrifugal force is a fictitious force.

Subutai
Posts: 3,235
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11/16/2014 9:44:57 AM
Posted: 2 years ago
The centrifugal force is not real. To maintain circular motion, an inward force is required (think of the sun and planets). The centrifugal force is actually a pseudo-force, that arises from being in an accelerating frame. I'm not actually sure why this is, but I can say with certainty that the centrifugal force is not real.
I'm becoming less defined as days go by, fading away, and well you might say, I'm losing focus, kinda drifting into the abstract in terms of how I see myself.
DanneJeRusse
Posts: 12,633
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11/19/2014 1:30:19 PM
Posted: 2 years ago
At 11/16/2014 5:36:54 AM, chui wrote:
Just wondered if anyone disagreed with this view point?

In a way I would agree, considering the actually force is centripetal force, whereas centrifugal force 'balances' out the effects of centripetal.

It's like the ball being spun round on a string, the centripetal force is "forcing" the ball to follow a curved path, while the ball's inertia wants to break away from the centripetal force of the string in order to follow a straight path.
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Enji
Posts: 1,022
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11/19/2014 3:57:25 PM
Posted: 2 years ago
Suppose you have a ball on a string and the ball is spun around in a circle. The ball experiences a centripetal force (towards the centre) orthogonal to its direction of travel causing it to travel a circular path. Newton's third law tells us that forces come in pairs; the centre point where the string is attached is experiencing a force equal and opposite to the centripetal force which is pulling away from the centre. Why wouldn't you call this a centrifugal force?
chui
Posts: 507
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11/20/2014 12:12:04 AM
Posted: 2 years ago
At 11/19/2014 3:57:25 PM, Enji wrote:
Suppose you have a ball on a string and the ball is spun around in a circle. The ball experiences a centripetal force (towards the centre) orthogonal to its direction of travel causing it to travel a circular path. Newton's third law tells us that forces come in pairs; the centre point where the string is attached is experiencing a force equal and opposite to the centripetal force which is pulling away from the centre. Why wouldn't you call this a centrifugal force?

The centre point is not moving in a circle. By centrifugal force I was refering to a force on the moving object in the accelerated frame.
Enji
Posts: 1,022
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11/20/2014 8:50:57 AM
Posted: 2 years ago
At 11/20/2014 12:12:04 AM, chui wrote:
At 11/19/2014 3:57:25 PM, Enji wrote:
Suppose you have a ball on a string and the ball is spun around in a circle. The ball experiences a centripetal force (towards the centre) orthogonal to its direction of travel causing it to travel a circular path. Newton's third law tells us that forces come in pairs; the centre point where the string is attached is experiencing a force equal and opposite to the centripetal force which is pulling away from the centre. Why wouldn't you call this a centrifugal force?

The centre point is not moving in a circle. By centrifugal force I was refering to a force on the moving object in the accelerated frame.

The centrifugal force isn't exerted on the object moving in a curved path; it's exerted by that object onto the object(s) causing the curved motion. You've simply redefined what you meant by centrifugal force as the centripetal force. However, since the reactive force to the centripetal force is also pulling in the opposite direction (centripetal meaning towards the centre and centrifugal meaning away from the centre) it would accurately be called a centrifugal force.
chui
Posts: 507
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11/21/2014 1:23:40 AM
Posted: 2 years ago
At 11/20/2014 8:50:57 AM, Enji wrote:
At 11/20/2014 12:12:04 AM, chui wrote:
At 11/19/2014 3:57:25 PM, Enji wrote:
Suppose you have a ball on a string and the ball is spun around in a circle. The ball experiences a centripetal force (towards the centre) orthogonal to its direction of travel causing it to travel a circular path. Newton's third law tells us that forces come in pairs; the centre point where the string is attached is experiencing a force equal and opposite to the centripetal force which is pulling away from the centre. Why wouldn't you call this a centrifugal force?

The centre point is not moving in a circle. By centrifugal force I was refering to a force on the moving object in the accelerated frame.

The centrifugal force isn't exerted on the object moving in a curved path; it's exerted by that object onto the object(s) causing the curved motion. You've simply redefined what you meant by centrifugal force as the centripetal force. However, since the reactive force to the centripetal force is also pulling in the opposite direction (centripetal meaning towards the centre and centrifugal meaning away from the centre) it would accurately be called a centrifugal force.

Having taught physics for nearly 30 years I have read many textbooks. Not one of them describes centrifugal force the way you do. Perhaps you might find a source to back your definition?
All the definitions I have read clearly state that centrifugal force is a fictitious force used in accelerated frame calculations.
chui
Posts: 507
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11/21/2014 1:30:30 AM
Posted: 2 years ago
At 11/20/2014 12:57:16 PM, Greyparrot wrote:
Is normal force real when you put your foot on the ground?

I would say it is. In a Newtonian view this is because gravity causes weight and due to weight a contact force is created against the ground. The normal force is a 3rd law reaction to the contact force. In an Einsteinian view gravity also is seen as a fictitious force and the argument moves into space-time curvature and accelerated frames etc.
chui
Posts: 507
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11/30/2014 2:25:55 AM
Posted: 2 years ago
At 11/28/2014 10:59:37 PM, gomergcc wrote:
Then what is the force in this video

The camera is moving with the trainees in an accelerated frame. From this perspective it appears that they are being pushed down relative to the frame. It is convenient to label this force the centrifugal force. But if we ask the question what causes this force there is no sensible answer.
From a non accelerating frame e.g. The trainers frame we see that the trainee is accelerating upward relative to the camera picture. Newton's laws of motion tell us this requires an upward force . If there were a downward force as well they would be in equilibrium and would not accelerate.
slo1
Posts: 4,354
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11/30/2014 9:42:27 PM
Posted: 2 years ago
Such real world implications for just a fictitious force. Us mere lay people can't quite grasp it as fictitious or even how a particular frame that has motion in it does not have inertia.
slo1
Posts: 4,354
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11/30/2014 9:58:52 PM
Posted: 2 years ago
At 11/30/2014 9:42:27 PM, slo1 wrote:
Such real world implications for just a fictitious force. Us mere lay people can't quite grasp it as fictitious or even how a particular frame that has motion in it does not have inertia.

I think I meant to say how a particular frame of reference feels like a force and another frame of reference sees it as just inertia.

going to bed
chui
Posts: 507
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11/30/2014 11:57:21 PM
Posted: 2 years ago
At 11/30/2014 10:02:19 PM, slo1 wrote:
http://www.regentsprep.org...

Nice link.

Common sense is often a poor guide to understanding the world. It took a genius called Newton to see the real nature of force and inertia. He ended over a thousand years of debate that had started with the Greeks.