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Regarding this edit, asserting that:
ω x (ω x r) is always perpendicular to ω
I don't think this is true.
If F_centrifugal = mω x (ω x r)
then by the rules of the [ triple product]:
=F_centrifugal=m( =m().
Yes, the second term is always radially outward, since it has magnitude in the r direction, but the first time doesn't have to be 0 so long as and r are not perpendicular.
For example, consider an objective in helical motion such that it is completing counterclockwise circles in xy plane as viewed from +z direction so that its r has a component n the z direction so that has a component in the xy plane. That would make and thus ω x (ω x r) has a component in the direction and is not only radially outward.-- Louiedog ( talk) 11:43, 5 June 2017 (UTC)
The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for speedy deletion:
You can see the reason for deletion at the file description page linked above. — Community Tech bot ( talk) 15:53, 9 December 2022 (UTC)
I changed the lead sentence because it's inertial motion and not observation that gives rise to centrifugal force. If an object is drawn to the edge of a rotating system by centrifugal force, this can be observed from any vantage point. Newton's rotating bucket is a prime example. You don't have to be rotating inside the bucket in order to observe the water being pushed against the bucket's walls. 2A00:23CC:4D80:1101:8D3C:FAAF:EB21:11FE ( talk) 21:45, 14 December 2023 (UTC) On another point, the last sentence in the top paragraph talks about something called reactive centrifugal force, as though it's something different. It's just the same centrifugal force pushing or pulling against a centripetal force. It would be there anyway, even if the centripetal force wasn't there, and so it's not a reaction. The centripetal force curves the path of the object and it doesn't even have to be equal in magnitude to the centrifugal force unless it is causing circular motion. 2A00:23CC:4D80:1101:8D3C:FAAF:EB21:11FE ( talk) 21:52, 14 December 2023 (UTC)
Well I'm afraid I'll have to disagree with you. The first paragraph mentions mechanical devices that operate on the basis of centrifugal force. How would these work if centrifugal force is only something that depends on the choice of coordinate frame? Surely centrifugal force has to be caused by inertial motion and not by choice of coordinate frame. 2A00:23CC:4D80:1101:58A2:F0FE:6C9A:FB30 ( talk) 10:36, 15 December 2023 (UTC)
In a centrifuge, the material that is rotating with the machine, flies out to the edge because of its tendency to continue in its straight line inertial path. It pushes against the edge of the machine and Archimedes' principle is invoked, segregating the heavier particles from the lighter particles. That's an example of centrifugal force. I don't see this as being an effect that depends on the choice of coordinate frame for analysis. Same principle with a centrifugal clutch or a centrifugal governor. However you might analyse these, there is a force pressing outwards that has a mechanical effect. Are you one hundred percent sure about what you have said above? Think about it. I simply can't agree with you. 2A00:23CC:4D80:1101:B0C8:EC5D:84BA:4D00 ( talk) 13:01, 15 December 2023 (UTC)
I don't think that maths needs to come into it at all. And I don't think our intuition is failing us when we observe the phenomenon of centrifugal force having a real physical effect. The non-physics public have usually been aware of centrifugal force since they were children, when they saw somebody swing a bucket of water over their heads and the water not falling out. It seems to me that you have got too distracted by the mathematical analysis, to the extent that you have made yourself believe that centrifugal force as a practical reality is merely a figment of a particular method of mathematical analysis. Before you wrote what you wrote above, I was going to sarcastically suggest that you remove all those references to centrifugal clutches and centrifugal governors etc., just in case the readers might get ideas that conflict with the fictitious narrative which the article seems to be promoting. Anyway, I've said all I can say and so I'll leave you to think about it. 2A00:23CC:4D80:1101:59EA:8F9E:A7A5:D64F ( talk) 16:14, 15 December 2023 (UTC)
OK, I see what you are saying now. You are saying that centrifugal force doesn't conform to the definition of force as per Newton's laws of motion. And of course, that should be stated in the article. But I've been thinking more about the matter, and I think you are giving undue weight to a scientific definition of force, over the head of the common understanding of the very real phenomenon known as centrifugal force. Look at it this way. A car swerves round a corner at high speed and a passenger gets flung out the back door. We would all agree that this was because of the passenger's tendency to continue in their straight line inertial path. And this tendency caused the passenger to push against the car door, causing the car door to open and the passenger to be thrown out into the road. Now we'll all agree that this tendency was very real. But are we not allowed to call this tendency centrifugal force? What exactly is it that you are claiming is only an illusion in a rotating frame of reference? We can't write off the tendency to be pushed against the door, simply on the grounds that it is only an illusion under a certain kind of mathematical analysis. The effect is very real, and it's now clear to me that this discussion is purely over semantics. It's all about whether or not we are allowed to refer to, what is commonly known as centrifugal force, by its common name. I think we're all agreed that centrifugal force, under the common understanding, arises as a result of inertial motion, and not because of any choice of coordinate frame. But I do see your argument that centrifugal force within the common understanding does not conform with the strictly scientific definition of force as per Newton's laws of motion. I think the common understanding of centrifugal force should come first in the article, followed by the clarification that it is a local term not strictly in line with the definition of force as is used in Newtonian mechanics. I say this, because as the article stands now, it is counter intuitive, giving the impression that what most people see as a real effect with a familiar name, can be made to become an illusion by mathematicians operating in a rotating frame of reference. Those devices listed in the introduction really do operate by centrifugal force under the common understanding. You cannot write that fact off by insisting that it doesn't conform to a strict scientific definition of force. The issue is semantics, not physics. 2A00:23CC:4D80:1101:797D:908D:F9D2:B75A ( talk) 20:15, 15 December 2023 (UTC)
Mr. Ollie. The first sentence in this article confuses the issue. We're agreed that centrifugal force is not a Newtonian force. Therefore we need to remove the bit where it says "in Newtonian mechanics". The next bit where it says that centrifugal force is an inertial force is fine. But then it immediately delves into the issue that I first raised. Just because it is an inertial force doesn't mean that it is an illusion only observed in a rotating frame of reference. It's no illusion that centrifugal force can be used to simulate the weight of gravity in a rotating space station. I thought we had it all sorted when you correctly drew my attention to the fact that centrifugal force is not a Newtonian force. But it seems that you still think it is an illusion, dependent on choice of coordinate frame. This is clearly not the case. 2A00:23CC:4D80:1101:F0EB:BBD8:6848:CEA1 ( talk) 23:39, 15 December 2023 (UTC)
Mr. Ollie. It says in the first sentence, "appears to act on all objects when viewed in a rotating frame of reference". I interpret that as stating that it is only an illusion. But we know that it is not an illusion. It may not be a Newtonian force, but it is still a force, and it can have the same physical effect as a Newtonian force, as per the example I gave of weight being caused by rotation in a space station. I suggest that the introduction runs through the following key points,
″When an object is forced to rotate in a rotating system, a centrifugal force draws it away from the centre of rotation, due to the tendency of the object to continue along its uniform straight line inertial path. Centrifugal force is therefore an inertial force and not a Newtonian force, as the latter kind is not involved in uniform straight line motion. Centrifugal force is often analysed in a frame of reference that rotates with the rotating system″
In fact, that's about all there is to it. It's not a very extensive topic. 2A00:23CC:4D80:1101:8D8F:9CE:B079:7FFD ( talk) 00:28, 16 December 2023 (UTC)
Dolphin51, You misrepresented what I said above. I said that when the car swerves, centrifugal force throws the passenger against the door of the car, due to the tendency of the passenger to undergo his uniform straight line inertial path. We were already agreed that this centrifugal force is not a Newtonian force, but it is a force nevertheless. 2A00:23CC:4D80:1101:BDDC:2E1F:8186:E19E ( talk) 09:30, 16 December 2023 (UTC)
We've been down this path multiple times before. The archives are full of lengthy discussions with multiple editors, one in particular (FDT/David Tombe), that led to only marginal improvements in the article and certain editors (eg, FDT/David Tombe) being banned from physics-related articles and discussions. I'm not seeing anything new in this discussion, and in fact it seems to be largely rehashing those previous discussions. As we've fallen into trying to teach each other "correct" physics/semantics, I really don't see any further value in talk page discussion - this isn't a forum or discussion board. Perhaps an RFC or other dispute resolution avenue would be beneficial if you feel that there is a specific improvement needed in the article. -- FyzixFighter ( talk) 16:19, 16 December 2023 (UTC)
Was that article, by any chance, started up in order to package away out of sight all scenarios that exposed centrifugal force as a frame-independent force?You will find that launching conspiracy theories will not help your arguments. It seems that we are done here. MrOllie ( talk) 16:59, 16 December 2023 (UTC)
Well if I am wrong, then why aren't those examples simply included in this article? Why did they have to be sided off to a separate article? 2A00:23CC:4D80:1101:DD04:6DDA:A6E1:F358 ( talk) 17:05, 16 December 2023 (UTC)
This is the
talk page for discussing improvements to the
Centrifugal force article. This is not a forum for general discussion of the article's subject. |
Article policies
|
Find sources: Google ( books · news · scholar · free images · WP refs) · FENS · JSTOR · TWL |
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Index,
1,
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17Auto-archiving period: 60 days
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![]() | This page is not a forum for general discussion about centrifugal force. Any such comments may be removed or refactored. Please limit discussion to improvement of this article. You may wish to ask factual questions about centrifugal force at the Reference desk. |
Index
|
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This page has archives. Sections older than 60 days may be automatically archived by Lowercase sigmabot III when more than 4 sections are present. |
Regarding this edit, asserting that:
ω x (ω x r) is always perpendicular to ω
I don't think this is true.
If F_centrifugal = mω x (ω x r)
then by the rules of the [ triple product]:
=F_centrifugal=m( =m().
Yes, the second term is always radially outward, since it has magnitude in the r direction, but the first time doesn't have to be 0 so long as and r are not perpendicular.
For example, consider an objective in helical motion such that it is completing counterclockwise circles in xy plane as viewed from +z direction so that its r has a component n the z direction so that has a component in the xy plane. That would make and thus ω x (ω x r) has a component in the direction and is not only radially outward.-- Louiedog ( talk) 11:43, 5 June 2017 (UTC)
The following Wikimedia Commons file used on this page or its Wikidata item has been nominated for speedy deletion:
You can see the reason for deletion at the file description page linked above. — Community Tech bot ( talk) 15:53, 9 December 2022 (UTC)
I changed the lead sentence because it's inertial motion and not observation that gives rise to centrifugal force. If an object is drawn to the edge of a rotating system by centrifugal force, this can be observed from any vantage point. Newton's rotating bucket is a prime example. You don't have to be rotating inside the bucket in order to observe the water being pushed against the bucket's walls. 2A00:23CC:4D80:1101:8D3C:FAAF:EB21:11FE ( talk) 21:45, 14 December 2023 (UTC) On another point, the last sentence in the top paragraph talks about something called reactive centrifugal force, as though it's something different. It's just the same centrifugal force pushing or pulling against a centripetal force. It would be there anyway, even if the centripetal force wasn't there, and so it's not a reaction. The centripetal force curves the path of the object and it doesn't even have to be equal in magnitude to the centrifugal force unless it is causing circular motion. 2A00:23CC:4D80:1101:8D3C:FAAF:EB21:11FE ( talk) 21:52, 14 December 2023 (UTC)
Well I'm afraid I'll have to disagree with you. The first paragraph mentions mechanical devices that operate on the basis of centrifugal force. How would these work if centrifugal force is only something that depends on the choice of coordinate frame? Surely centrifugal force has to be caused by inertial motion and not by choice of coordinate frame. 2A00:23CC:4D80:1101:58A2:F0FE:6C9A:FB30 ( talk) 10:36, 15 December 2023 (UTC)
In a centrifuge, the material that is rotating with the machine, flies out to the edge because of its tendency to continue in its straight line inertial path. It pushes against the edge of the machine and Archimedes' principle is invoked, segregating the heavier particles from the lighter particles. That's an example of centrifugal force. I don't see this as being an effect that depends on the choice of coordinate frame for analysis. Same principle with a centrifugal clutch or a centrifugal governor. However you might analyse these, there is a force pressing outwards that has a mechanical effect. Are you one hundred percent sure about what you have said above? Think about it. I simply can't agree with you. 2A00:23CC:4D80:1101:B0C8:EC5D:84BA:4D00 ( talk) 13:01, 15 December 2023 (UTC)
I don't think that maths needs to come into it at all. And I don't think our intuition is failing us when we observe the phenomenon of centrifugal force having a real physical effect. The non-physics public have usually been aware of centrifugal force since they were children, when they saw somebody swing a bucket of water over their heads and the water not falling out. It seems to me that you have got too distracted by the mathematical analysis, to the extent that you have made yourself believe that centrifugal force as a practical reality is merely a figment of a particular method of mathematical analysis. Before you wrote what you wrote above, I was going to sarcastically suggest that you remove all those references to centrifugal clutches and centrifugal governors etc., just in case the readers might get ideas that conflict with the fictitious narrative which the article seems to be promoting. Anyway, I've said all I can say and so I'll leave you to think about it. 2A00:23CC:4D80:1101:59EA:8F9E:A7A5:D64F ( talk) 16:14, 15 December 2023 (UTC)
OK, I see what you are saying now. You are saying that centrifugal force doesn't conform to the definition of force as per Newton's laws of motion. And of course, that should be stated in the article. But I've been thinking more about the matter, and I think you are giving undue weight to a scientific definition of force, over the head of the common understanding of the very real phenomenon known as centrifugal force. Look at it this way. A car swerves round a corner at high speed and a passenger gets flung out the back door. We would all agree that this was because of the passenger's tendency to continue in their straight line inertial path. And this tendency caused the passenger to push against the car door, causing the car door to open and the passenger to be thrown out into the road. Now we'll all agree that this tendency was very real. But are we not allowed to call this tendency centrifugal force? What exactly is it that you are claiming is only an illusion in a rotating frame of reference? We can't write off the tendency to be pushed against the door, simply on the grounds that it is only an illusion under a certain kind of mathematical analysis. The effect is very real, and it's now clear to me that this discussion is purely over semantics. It's all about whether or not we are allowed to refer to, what is commonly known as centrifugal force, by its common name. I think we're all agreed that centrifugal force, under the common understanding, arises as a result of inertial motion, and not because of any choice of coordinate frame. But I do see your argument that centrifugal force within the common understanding does not conform with the strictly scientific definition of force as per Newton's laws of motion. I think the common understanding of centrifugal force should come first in the article, followed by the clarification that it is a local term not strictly in line with the definition of force as is used in Newtonian mechanics. I say this, because as the article stands now, it is counter intuitive, giving the impression that what most people see as a real effect with a familiar name, can be made to become an illusion by mathematicians operating in a rotating frame of reference. Those devices listed in the introduction really do operate by centrifugal force under the common understanding. You cannot write that fact off by insisting that it doesn't conform to a strict scientific definition of force. The issue is semantics, not physics. 2A00:23CC:4D80:1101:797D:908D:F9D2:B75A ( talk) 20:15, 15 December 2023 (UTC)
Mr. Ollie. The first sentence in this article confuses the issue. We're agreed that centrifugal force is not a Newtonian force. Therefore we need to remove the bit where it says "in Newtonian mechanics". The next bit where it says that centrifugal force is an inertial force is fine. But then it immediately delves into the issue that I first raised. Just because it is an inertial force doesn't mean that it is an illusion only observed in a rotating frame of reference. It's no illusion that centrifugal force can be used to simulate the weight of gravity in a rotating space station. I thought we had it all sorted when you correctly drew my attention to the fact that centrifugal force is not a Newtonian force. But it seems that you still think it is an illusion, dependent on choice of coordinate frame. This is clearly not the case. 2A00:23CC:4D80:1101:F0EB:BBD8:6848:CEA1 ( talk) 23:39, 15 December 2023 (UTC)
Mr. Ollie. It says in the first sentence, "appears to act on all objects when viewed in a rotating frame of reference". I interpret that as stating that it is only an illusion. But we know that it is not an illusion. It may not be a Newtonian force, but it is still a force, and it can have the same physical effect as a Newtonian force, as per the example I gave of weight being caused by rotation in a space station. I suggest that the introduction runs through the following key points,
″When an object is forced to rotate in a rotating system, a centrifugal force draws it away from the centre of rotation, due to the tendency of the object to continue along its uniform straight line inertial path. Centrifugal force is therefore an inertial force and not a Newtonian force, as the latter kind is not involved in uniform straight line motion. Centrifugal force is often analysed in a frame of reference that rotates with the rotating system″
In fact, that's about all there is to it. It's not a very extensive topic. 2A00:23CC:4D80:1101:8D8F:9CE:B079:7FFD ( talk) 00:28, 16 December 2023 (UTC)
Dolphin51, You misrepresented what I said above. I said that when the car swerves, centrifugal force throws the passenger against the door of the car, due to the tendency of the passenger to undergo his uniform straight line inertial path. We were already agreed that this centrifugal force is not a Newtonian force, but it is a force nevertheless. 2A00:23CC:4D80:1101:BDDC:2E1F:8186:E19E ( talk) 09:30, 16 December 2023 (UTC)
We've been down this path multiple times before. The archives are full of lengthy discussions with multiple editors, one in particular (FDT/David Tombe), that led to only marginal improvements in the article and certain editors (eg, FDT/David Tombe) being banned from physics-related articles and discussions. I'm not seeing anything new in this discussion, and in fact it seems to be largely rehashing those previous discussions. As we've fallen into trying to teach each other "correct" physics/semantics, I really don't see any further value in talk page discussion - this isn't a forum or discussion board. Perhaps an RFC or other dispute resolution avenue would be beneficial if you feel that there is a specific improvement needed in the article. -- FyzixFighter ( talk) 16:19, 16 December 2023 (UTC)
Was that article, by any chance, started up in order to package away out of sight all scenarios that exposed centrifugal force as a frame-independent force?You will find that launching conspiracy theories will not help your arguments. It seems that we are done here. MrOllie ( talk) 16:59, 16 December 2023 (UTC)
Well if I am wrong, then why aren't those examples simply included in this article? Why did they have to be sided off to a separate article? 2A00:23CC:4D80:1101:DD04:6DDA:A6E1:F358 ( talk) 17:05, 16 December 2023 (UTC)