Circumventing Newton's third law through Euler Inertial Forces

[John2020]

6 minutes ago, Ghideon said:

So the simplest thing you could imagine is that all of Newton, Lagranage, Hamilton, Einstein, and down to the core of knowledge is wrong*. Your definition of "simple" seems to deviate from my definition. 

I didn't say that. The problem is I searched in the entire web to find physics exercises that address this kind of problem (as I proposed with my last drawing), however I found none. Do you have any resource that may show a detail solution to this specific problem (non-rotating and rotating frame of reference)?

10 minutes ago, Ghideon said:

Does your answer imply that you are not prepared to move back to basics and try again? 

When something does not fit well, I have always doubt (and eventually I am right about it). I need a detailed and clear mathematical analysis based on classical mechanics (No Lagrangians, no Hamiltonians and stuff). If you have any resource on this, please share it with us. The way we handled this problem through the thread was 99.9% based on texting and not maths, meaning what we exchanged was just views/interpretations, no proofs and no real life observations.

13 minutes ago, Ghideon said:

Thats cool, we knew that your claims were incorrect according to known laws of physics from your very first post. Question was if you wanted to stay wrong or eventually learn more physics. 

No thanks. I already learnt a lot.

13 minutes ago, Ghideon said:

Me and @swansont will reach the same conclusion regarding inertial vs rotational frame of reference as long as we are able to make identical interpretations of your instructions. It can't be any other way since we use the same physical rules, principles and laws. I guess performing such an analysis will have to wait till such a time when your level of understanding matches the required explanations.

When you make the analysis on the rotating frame, I am convinced 99.9999% that your view on this matter will be wrong because you follow of what is familiar to you, thinking that will never fail and you will ensure that you will not get embarrassed (don't forget you are a member of this forum having a good reputation). 

 

15 minutes ago, Ghideon said:

Have you seen any support for your Newton circumvention here during the discussions here?
Also not that this is just about some minor details of one specific example. The big picture regarding all possible examples and designs of this type was analysed and presented to you long ago. 

That does not mean anything. Those who know very good physics may fall into the trap of not questioning something for many reasons even if there is a small doubt on their head because of an observation/experience (equals experiment), however they afraid to express it publicly over the forum. It would be like being against the stream. Unfortunately, most humans are afraid more of their reputation (especially when one is specialist on the field) than to explore something that may look initially far-fetched or ridiculous. 

Next time, take the hammer with the short leather grip (semi non-rigid) and make the experiment by yourself. I suppose there will be enough centrifugal force left in the rotating frame that will show you the way forward (enlightenment).

 

[swansont]

6 hours ago, John2020 said:

While accelerates radially is there a reaction force upon the rest of the system?

There is always a reaction force in an inertial frame. The rod exerts a frictional force on the mass, the mass exerts a frictional force on the rod.

4 hours ago, John2020 said:

I don't think is the same question.

You keep asking if there’s a reaction force, like you’re hoping that someone will eventually say, “no”

4 hours ago, John2020 said:

Do you speak seriously? How can that be? The rod cannot move radially, thus cannot pull.

A table leg doesn’t move, but exerts a force to keep whatever’s on the table from falling to the ground.

Your assessment of what is and is not possible needs to be based in physics, not fantasy.

 

 

4 hours ago, John2020 said:

I already did. I am expecting no reaction upon the rest of the system while the mass m is being accelerated because the acceleration of the mass m is caused by the increasing centripetal (by subtracting the kinetic friction force). In other words, the change in centripetal appears as an inertial force in the inertial frame that by nature has no counter part (reaction force).

The same I expect to happen in the rotating frame but now with the centrifugal force that is by nature inertial having no counter part (reaction force).

Centripetal is a label, not a kind of force. Tension can be a centripetal force. Friction, gravity, electrostatic, even a normal force can be the centripetal force in a problem. It’s just a label, important because circular motion means certain equations apply to the problem.

[John2020]

5 hours ago, swansont said:

A table leg doesn’t move, but exerts a force to keep whatever’s on the table from falling to the ground.

Your assessment of what is and is not possible needs to be based in physics, not fantasy.

 

5 hours ago, swansont said:

There is always a reaction force in an inertial frame. The rod exerts a frictional force on the mass, the mass exerts a frictional force on the rod.

 

5 hours ago, swansont said:

You keep asking if there’s a reaction force, like you’re hoping that someone will eventually say, “no”

In our case you overlook an important detail, there is a mass transfer that implies an accelerating change of the CoM. The situation has nothing to do with the normal forces and the table. You are fantasizing things that do not hold. Lastly, I am not hoping someone will eventually say, "no", but to acknowledge the obvious.

Next time, I would suggest you to make the same exercise with the hammer (as Ghideon proposed) or to think the situation of a passenger in a car while is taking a curve by changing the speed slightly.. 

Edited October 22, 2020 by John2020

[Ghideon]

12 hours ago, John2020 said:

I didn't say that.

Unintentional or not, that is what you say, just check the answers from some of the other members. Implications of your invalid physics runs much deeper that you want to or are capable of seeing. Which is also one aspect that makes the thread interesting; there are so many completely different ways to describe where and how the proposed ideas fail to match theory and observation. From this thread one could possibly create an interesting infographic from pre-Newton to the latest take on cosmology and particle physics and in each section describe how reactionless drives have become more and more improbable. (Maybe I should start a separate thread on that)

 

12 hours ago, John2020 said:

The way we handled this problem through the thread was 99.9% based on texting and not maths, meaning what we exchanged was just views/interpretations, no proofs and no real life observations.

There have been plenty of math presented, Swansont gave you equations a few pages ago. We will start apply more mathematics once we have a proper description of the example. When asking for details the examples tend to get more and more complicated and details change. One could even believe that there is tweaking of the examples to get members to provide incorrect analysis. Hence we apply more rigour in the initial steps; applying correct mathematics to an incorrectly defined system way allow for unphysical results, that is easy to do. We are not going to get tricked into doing that, intentionally or unintentionally. 

 

12 hours ago, John2020 said:

When something does not fit well, I have always doubt (and eventually I am right about it).

Ok. Confidence is a good thing I suppose.

12 hours ago, John2020 said:

When you make the analysis on the rotating frame, I am convinced 99.9999% that your view on this matter will be wrong because you follow of what is familiar to you, thinking that will never fail and you will ensure that you will not get embarrassed (don't forget you are a member of this forum having a good reputation). 

So you are right and I am wrong because you say so, not very persuading way to argue against all current physics. Being incorrect is not that embarrassing, especially not on this forum, due to the friendly atmosphere among the members. And if I would find an error so that I was wrong and Newton does not apply (according to your claims) and also were able to confirm that, then it is a Nobel Prize level of discovery. And missing the Nobel prize, that would be embarrassing I guess. But that's just a fairy tale, nothing to do with science. 

Since you don't get the big picture though physics I'll try an analogy this time.

We have natural positive numbers 1,2,3... and we have addition "+". There are rules how to perform addition and there are limits regarding the outcome. The sum of two positive numbers is positive. In this analogy your claims would be that the addition of two positive number sometimes should result in a negative sum. Members here try to show that the framework of mathematics does not work that way. Your answer is like "OK, my idea failed for 123+145 but wait I have another case, here are these two positive numbers their sum is suspicious, I believe the sum is negative, please analyse". This is how your physics looks from the outside. No matter how hard you look for different positive integers there is no way to find a pair that added together gets you a negative sum. And no matter how hard you try creating a classical mechanical system that have the properties you claim we know that within the framework of classical mechanics such a system cannot be described*.

 

5 hours ago, John2020 said:

Lastly, I am not hoping someone will eventually say, "no", but to acknowledge the obvious.

"the obvious" ? 

 

5 hours ago, John2020 said:

Next time, I would suggest you to make the same exercise with the hammer (as Ghideon proposed) or to think the situation of a passenger in a car while is taking a curve by changing the speed slightly.. 

And we will get the result that the laws of physics predict. (Mainstream edition, not your personal interpretation)

 

 

*) Within the applicability of course. You could, correctly, argue that Newton is wrong at relative velocities close to speed of light in vacuum. The natural numbers is an analogy, there may be situations outside the everyday usage of mathematics where it does not apply. For instance it may happen in certain computer architectures due to limited number of bits available for representations. But that is not the point with the analogy in this case. 
 

Edited October 22, 2020 by Ghideon
grammar, spelling

[John2020]

6 minutes ago, Ghideon said:

"the obvious" ? 

The obvious can be identified in the rotating frame easily: On my example as long as the angular velocity changes, the  centrifugal force increases (net force is not null -> centrifugal > centripetal) results in accelerating mass m radially. At that particular time frame this change is not counteracted by a force upon the rest of the system because the centrifugal is by nature inertial (not a real force. If it was a real force then I would agree with you. This is the point you all miss.). Thus, the acceleration of mass m results in an accelerating change of the CoM of the system as a whole.

[Ghideon]

50 minutes ago, John2020 said:

not a real force.

Non-real forces (fictitious) have no physical effect. You seem to have missed that point. ( but you agreed on it in the earlier analysis)

 

[John2020]

7 minutes ago, Ghideon said:

Non-real forces (fictitious) have no physical effect. You seem to have missed that point. ( but you agreed on it in the earlier analysis)

Then how you explain the acceleration of mass m? The fact we experience the centrifugal force while being in a car driving over a curve, it is a physical effect. Otherwise, it is like being in denial that inertial forces exist. What I agreed was we don't have fictitious forces in an inertial frame.

Edited October 22, 2020 by John2020

[Ghideon]

2 hours ago, John2020 said:

Then how you explain the acceleration of mass m? 

The mass m is accelerated, in the inertial frame of reference, towards the circle centre by non-fictitious force labeled the centripetal force. Forces that are present also in the rotating frame of reference. In the rotating frame of reference the coordinates for the motion of the mass m does not match the motion in the inertial frame of reference. We can fix that difference by adding a fictitious force in the rotating frame. This fictitious force does not affect physical "reality". Events happening i the rotating frame happens in the inertial frame and vice versa.

Note that in the inertial frame of reference the mass m never accelerates out from the centre in your example. An accelerometer onboard the mass m will never register an acceleration* away from the circle centre, only a varying acceleration towards the centre. 

2 hours ago, John2020 said:

The fact we experience the centrifugal force while being in a car driving over a curve, it is a physical effect.

I have never experienced that. I have experienced a centripetal force resulting in a net force F>0 resulting in a change of direction AKA acceleration. (Given seatbelt is fastened and / or car door shut)

I have also, as an engineer, experienced the efficiency of introducing a fictitious force such as centrifugal force to allow for calculations in an accelerated frame of reference.

2 hours ago, John2020 said:

Otherwise, it is like being in denial that inertial forces exist. What I agreed was we don't have fictitious forces in an inertial frame.

I am denying that inertial forces has physical effect and that nature is consistent. Have you observed some event, for instance a car sliding off the road, happen when seen from beside the road while not happening for this in the car? I have not. An nature seems to strictly force such paradoxes. Luckily our laws of physics covers that and maintain consistency when we change coordinate systems. For instance by introducing fictitious force in on frame of reference and not in another.

 

*) In a perfectly tuned setting the acceleration could possibly be exactly zero (onboard the mall and in the inertial frame of reference) during a short time. 

Edited October 22, 2020 by Ghideon

[swansont]

10 hours ago, John2020 said:

In our case you overlook an important detail, there is a mass transfer that implies an accelerating change of the CoM. The situation has nothing to do with the normal forces and the table. You are fantasizing things that do not hold. Lastly, I am not hoping someone will eventually say, "no", but to acknowledge the obvious.

Next time, I would suggest you to make the same exercise with the hammer (as Ghideon proposed) or to think the situation of a passenger in a car while is taking a curve by changing the speed slightly.. 

I stated that my analysis that I assumed m<<M, so there is no change is the CoM, but that the rotation details would change if that assumption didn’t hold

My example with the table is to rebut your claim the if the rod can’t move it can’t pull, which is ludicrous. Motion isn’t required in order to exert a force. The rod exerts a tension, and via friction, this is the source of the centripetal force.

Lecturing me on “next time” is out of line. You asked me to analyze this (poorly documented) scenario. I didn’t drop it into the thread unbidden.

 

 

 

 

18 hours ago, John2020 said:

When you make the analysis on the rotating frame, I am convinced 99.9999% that your view on this matter will be wrong because you follow of what is familiar to you, thinking that will never fail and you will ensure that you will not get embarrassed (don't forget you are a member of this forum having a good reputation). 

You have no credibility to make such an assessment. You don’t understand physics - you’ve made that abundantly clear. Most of what you have done is object when physics disagrees with your misconceptions. And yet you insist your misconceptions represent proper physics.

What’s “familiar” to everyone else in the thread is physics that works. If you want to show something to be wrong, do an analysis that’s actually compliant with Newton’s laws (nothing made up) or show, experimentally, that Newton’s laws are wrong. Those are your options. Anything else is BS. The burden of proof is yours.

5 hours ago, John2020 said:

The obvious can be identified in the rotating frame easily: On my example as long as the angular velocity changes, the  centrifugal force increases (net force is not null -> centrifugal > centripetal) results in accelerating mass m radially. At that particular time frame this change is not counteracted by a force upon the rest of the system because the centrifugal is by nature inertial (not a real force. If it was a real force then I would agree with you. This is the point you all miss.). Thus, the acceleration of mass m results in an accelerating change of the CoM of the system as a whole.

Perhaps you  an explain what you mean by “the centrifugal is by nature inertial” because it makes no sense to me.

4 hours ago, John2020 said:

Then how you explain the acceleration of mass m? The fact we experience the centrifugal force while being in a car driving over a curve, it is a physical effect. Otherwise, it is like being in denial that inertial forces exist. What I agreed was we don't have fictitious forces in an inertial frame.

What we experience is trying to move in a straight line, and having the car exert a force on us to move us in a circle. There is no real force outward. Illusions are not physical effects. Your senses are tricked by being in a rotating frame but interpreting everything you experience as if you were in an inertial frame.

[John2020]

2 hours ago, Ghideon said:

I have never experienced that. I have experienced a centripetal force resulting in a net force F>0 resulting in a change of direction AKA acceleration. (Given seatbelt is fastened and / or car door shut)

I have also, as an engineer, experienced the efficiency of introducing a fictitious force such as centrifugal force to allow for calculations in an accelerated frame of reference.

Being inside a car driving in a curve you are in a rotational frame that implies what you experience is a centrifugal force that creates a pretty physical outwards acceleration when you are on board.

2 hours ago, Ghideon said:

Note that in the inertial frame of reference the mass m never accelerates out from the centre in your example. An accelerometer onboard the mass m will never register an acceleration* away from the circle centre, only a varying acceleration towards the centre. 

*) In a perfectly tuned setting the acceleration could possibly be exactly zero (onboard the mall and in the inertial frame of reference) during a short time. 

There is a problem here. In both cases the coordinates of the mass m will appear away from the center because we have a change in angular velocity. How you say the acceleration is towards the center in both cases? Such claim brings the inertial and rotational in disagreement. I suppose this is a mistake in your description.

I would understand the above for the inertial frame, however when we are in the rotating frame the role of varying centripetal (the difference actually between two subsequent angular velocity values) is taken by the varying centrifugal force.

There are some points that for me up to now have no satisfactory explanation as given from your side (as forum).

Rotating frame in my example (fictitious forces)

a) The role of centripetal is taken by the friction force

b) When the angular velocity is constant, the centripetal and the inertial centrifugal force are equal that keeps the mass at point r1 or moves with constant velocity (assuming to be very small due to limited rod length)

c) During the transition to a greater angular velocity value, the centrifugal becomes greater than the centripetal

d) Due to (c) the mass m will acquire a radial outwards acceleration (since we have a change in angular velocity)

e) Due to (d) for a mass ratio e.g. M/m=10/1, the CoM changes and accelerates in the same direction as the mass m

Conclusion: Since the acceleration of mass m is caused by the inertial centrifugal force (considered fictitious), there will be no counteracting force upon the rest of the system that implies a change and acceleration of CoM of a system is feasible.

Note: swansont assumed m<<M in his analysis so there will be no change and in CoM that is OK. 

 

Edited October 22, 2020 by John2020

[Ghideon]

1 minute ago, John2020 said:

Being inside a car driving in a curve you are in a rotational frame that implies what you experience is a centrifugal force that creates a pretty physical outwards acceleration when you are on board.

False.

 

3 minutes ago, John2020 said:

How you say the acceleration is towards the center in both cases?

Did I say that? I discussed the inertial frame of reference.

[swansont]

10 minutes ago, John2020 said:

Conclusion: Since the acceleration of mass m is caused by the inertial centrifugal force (considered fictitious), there will be no counteracting force upon the rest of the system that implies a change and acceleration of CoM of a system is feasible.

That’s not a valid conclusion, as your analysis is incomplete. You haven’t accounted for the change in angular speed. So you now have rotation in your rotating frame (have fun analyzing that). There must be a tangential force acting in order for this to happen. Both of these elements have yet to be addressed. (you could, of course, choose a simpler system to analyze)

 

 

[John2020]

12 hours ago, swansont said:

You haven’t accounted for the change in angular speed. So you now have rotation in your rotating frame (have fun analyzing that). There must be a tangential force acting in order for this to happen.

I don't understand what you actually mean. Both are provided by the motor (inner mechanism, power etc) and transferred through the rigid rod.

[Ghideon]

13 hours ago, John2020 said:

d) Due to (c) the mass m will acquire a radial outwards acceleration (since we have a change in angular velocity)

Here is one source of confusion. When you say that mass m will accelerate outwards, you mean as seen in the rotating frame, OK? 

What will an accelerometer, attached to the mass m, show? Number not important yet, just direction. 

 

34 minutes ago, John2020 said:

I don't understand what you actually mean.

Does the concept of "Euler force" ring a bell? Given the title of your speculative thread the tangent force Swansont mentions should not be too unfamiliar.

 

[John2020]

8 minutes ago, Ghideon said:

Here is one source of confusion. When you say that mass m will accelerate outwards, you mean as seen in the rotating frame, OK? 

What will an accelerometer, attached to the mass m, show? Number not important yet, just direction. 

Before I wrote those points, I mentioned "Rotating Frame (Fictitious Forces)". So, for the rotating frame it will be outwards as also the accelerometer (we speak always for mass m) will show the same direction.

[Ghideon]

2 minutes ago, John2020 said:

Before I wrote those points, I mentioned "Rotating Frame (Fictitious Forces)".

Yes

2 minutes ago, John2020 said:

So, for the rotating frame it will be outwards as also the accelerometer (we speak always for mass m) will show the same direction

No. 

[John2020]

12 minutes ago, Ghideon said:

Does the concept of "Euler force" ring a bell? Given the title of your speculative thread the tangent force Swansont mentions should not be too unfamiliar.

But the Euler force is being developed along the axis of rotation. We don't have any mass there that would be influenced. That could be utilized if the mass m and the rod would on the z-axis (as seen from screen). It means the rod and the mass along the axis of rotation of mass M. It is a good alternative for my next challenge.

3 minutes ago, Ghideon said:

No. 

Don't forget I speak for the transition time where the centrifugal > centripetal and not while they are equal (thus zero acceleration).

[Ghideon]

26 minutes ago, John2020 said:

Don't forget I speak for the transition time where the centrifugal > centripetal and not while they are equal (thus zero acceleration).

Do you know what an accelerometer does?

Do you know that acceleration is absolute?

The measured acceleration may vary and is always towards the center*. The acceleration may look different from different frames of reference such as a rotating or an inertial frame of reference. 

I speak of your example below. Both at the time(s) with constant angular velocity and the time of accelerating angular velocity. 

26 minutes ago, John2020 said:

But the Euler force is being developed along the axis of rotation.

No.

In classical mechanics, the Euler force is the fictitious tangential force[1] that appears when a non-uniformly rotating reference frame is used for analysis of motion and there is variation in the angular velocity of the reference frame's axes. 

https://en.wikipedia.org/wiki/Euler_force

 

 

*) Again, as noted earlier In a perfectly tuned setting the accelerometer attached to mass m could possibly measure exactly zero during a short time. 

Edited October 23, 2020 by Ghideon
spelling, added link to Euler force, foot note

[John2020]

1 hour ago, Ghideon said:

*) Again, as noted earlier In a perfectly tuned setting the accelerometer attached to mass m could possibly measure exactly zero during a short time. 

That cannot be true along the rigid rod (we speak always about the mass m accelerating radially). 

[Ghideon]

10 minutes ago, John2020 said:

That cannot be true along the rigid rod (we speak always about the mass m accelerating radially). 

Of course it can. But not important to the discussion as we are not interested in fine tuning the example. May I advice you to focus one the other more serious issues pointed out?

[John2020]

7 minutes ago, Ghideon said:

May I advice you to focus one the other more serious issues pointed out?

You mean about the Euler force?

[Ghideon]

25 minutes ago, John2020 said:

You mean about the Euler force?

Not only that, but more imprtantly:

2 hours ago, John2020 said:

So, for the rotating frame it will be outwards as also the accelerometer (we speak always for mass m) will show the same direction.

False. An accelerometer attached to the mass m measures shows an inwards direction at all times.

Don't try to avoid addressing that important misunderstanding. It seems to be a major source of the errors in your analysis?

Do you know what an accelerometer does?

Do you know that acceleration is absolute?

The measured acceleration may vary and is always towards the center*. The acceleration may look different from different frames of reference such as a rotating or an inertial frame of reference. 

I speak of your example below. Both at the time(s) with constant angular velocity and the time of accelerating angular velocity. 

[John2020]

2 minutes ago, Ghideon said:

The measured acceleration may vary and is always towards the center*. The acceleration may look different from different frames of reference such as a rotating or an inertial frame of reference. 

Your argumentation is all about an inertial frame. I speak about the rotating frame. So there it cannot be towards the center since there we have the centrifugal that is greater than the centripetal during the increase in angular velocity.

[Ghideon]

1 minute ago, John2020 said:

Your argumentation is all about an inertial frame. I speak about the rotating frame. So there it cannot be towards the center since there we have the centrifugal that is greater than the centripetal during the increase in angular velocity.

Wrong. My description of the physics is correct for any frame of reference. Your description is incorrect in all frames of reference. 

Do you really think the accelerometer, attached to the mass m, will measure a different acceleration in different frames of reference? That would imply that nature is full of paradoxes. I can't imagine you have this fundamental misunderstanding of physics, hence i asked: Do you know what an accelerometer does?

 

[John2020]

2 minutes ago, Ghideon said:

Do you really think the accelerometer, attached to the mass m, will measure a different acceleration in different frames of reference? That would imply that nature is full of paradoxes.

No. In the inertial frame the accelerometer will show an inward (e.g. minus) and in the rotating frame an outward (plus).