martillo

As I already said very clearly, we are not dealing with Galilean transformations between inertial frames of references with relative constant velocities between them. We are considering an accelerated frame of reference. I can't believe we are discussing this... I think we are going out of the scope of the thread... If the two charges move freely they both accelerate by attraction or repulsion depending on the type of the charges. In a frame attached to any of the charges the acceleration of its charge is zero. The charge is attached to the frame, it doesn't move in its own frame...

Any force when applied to moving objects is frame dependent while considering accelerated frames.

I'm talking about dynamics of moving objects where F = ma is valid. Not valid for "structural" forces. F = ma, a = dv/dt = d2x/dt2 . A force F is frame dependent as acceleration a is frame dependent. If the frame is the accelerated one on the free falling then F = a = 0. I think Galileans frames are those moving at constant velocities with no acceleration, am I wrong? @MigL presented an example about a gravitational force asking where it goes when jumping to a free fall. If gravitational force does not apply in GR then I assume he is not considering GR.

Force is something frame dependent. When I jump out of the plane I jump to a free falling frame (a switch of frame) where no force is perceived. I have no problem with that.

Well, in that case it depends on the theory (model) we are considering. Classical Physics would state that there would be a net centripetal force perpendicular to the trajectory producing the curvature in the trajectory around Earth. Relativity Theory would state there would be no net force and the trajectory is a geodesic in the curved space-time. Am I wrong in something? I'm saying this after a reading on the link @joigus posted to me. You are aware I know only the basics of Relativity Theory. By the way, I'm not questioning nor proposing any model or theory here, I'm just comparing the different approaches of those two models or theories. Well, in that case I can only say that I think there would be a problem with the model. How something that do not exist could exert a force on something that do exist? I would agree with you when you mentioned in the OP the citation about that there are things just "made up" in Physics but not everything, I think...

Right, my misconception was to say that in free fall the frame would be not an inertial one while it is. The situation is that in that frame I do not perceive any acceleration or gravitational force. No problem with that but the intention here is not to enter in GR theory. In this thread I consider this example of @MigL as similar to the case of the magician posted by @Phi for All in the sense that this frame alone does not let me perceive the complete picture of the real situation which would be me and the ball falling to Earth and that if I don't open the parachute I will be smashed to the ground, isn't it? So I just would say that a better observation to describe the situation would be to also consider the relative movement between me and Earth. In my frame I would see Earth accelerated to me and so a force would be acting on Earth now. The force didn't vanish, is just that because of the change of referential it is acting on Earth now (with a change in its observed magnitude of course).

How is that? The force didn't disappear. If I consider that I will not open the parachute and will smash in the ground! My frame is not an inertial one. It is being accelerated...

The same force is acting in both of us, me and the ball and we are both accelerating towards the ground. I hope the parachute works fine! 😄

When I jump out I stop making force to the ball. We will be both in free fall... The proper model acknowledge to use something that is not real? I don't understand... I think I can agree. I don't get the point of disagreement...

I think all methods of observation tell us approximately how things are but sometimes they do not have enough accuracy to reveal how the things really are. Some times, as in the case of the magician, some features weren't observed by the method (for instance our direct visual perception) and we don't have the complete picture of what is really happening. So, some times if we need a more accurate description we must change our method of observation by a more accurate one. You may say this is something that never reaches and end and I think that some times we could reach an end while other times may be not. Physics' researches and developments continue, isn't it? An unicorn do exist in literature but does not physically exist as objects in the real world, right? I don't think these concepts are "sterile". They are helping to understand some things...

For the laws to be considered real they must pass the experimental verification following the scientific method, isn't it? But as I already mentioned models and theories evolved with time in the history of Physics for more accurate ones and I think is a process that hasn't reached an end if this could ever happen. They would be real but not physically existing. They would be a real mathematical artifact used in cartography.

I didn't say they are not real. For me both fields and forces are real laws in the Universe and as laws they are not visible. I consider the fields don't physically exist while the forces do. As I said, the fields are the mathematical representation of the force that WOULD act on an object if it WOULD exist at some place of the space. If the object exists the forces exists, not in the contrary.

This take us on what is considered by "force"... I consider that objects exist in the Universe with laws that govern their behavior in it. You can see the objects but not the laws which are present but actually not visible. The laws determine that an object can interact with other one someway and the interaction is considered in Physics as "force". What you can actually see is the consequence of an interaction not the interaction itself because it is a law in the Universe, not an object..

You can observe how the leaves of a tree moves with the force of the air on them...

The point is that a description of some reality always involves some abstraction. Models are based on the abstraction considered. As more accurate the abstraction more accurate the description of the reality. What physically exist are the forces not the fields. The fields are a mathematical construction that represents the forces that would act at some place if a particular object would exist at that place. The forces act over particular objects at the particular places where they exist. The fields are defined over the entire space. Yes I think they do. The reality is known with more accuracy only as more accurate the observations are made. Follows more accurate abstractions and models developed to describe and explain them. As I said above the description of some reality always involve some kind of abstraction. All models have limitations but they describe reality as they can. Of course some models fails in the description of some things and that's why new models surged along the entire history of Physics. I would say that all models describes some reality to some degree of accuracy but sometimes some models are replaced by other ones more accurate. I'm not sure if I understand you properly. If not please let me know. What we observe depends on how we observe, for instance, if we use telescopes or not and the accuracy depends on the kind of telescopes we use. Our observations of "how things really are" are always limited to some accuracy. I consider theories as models to describe realities with some inherent level of accuracy. Some theories were considered right at some time but replaced by other better ones time after. Better theories will help better against those deceptions and subjectivities you mention. The entire history of Physics is a look for "how things really are" (the truth) in all his areas...

From the OP: I think the purpose of Physics is to describe the physical reality. Now, to describe something, whatever it would be, we always make some kind of abstraction and so a model always takes place. By physical reality I mean everything related to objects with their properties of shape, position, mass, energy, forces, etc. and their laws of interactions and behaviors. This means to not consider for instance the biological properties of the objects what is leaved for Biology. Similarly with Chemistry and all of the other Sciences. So, right at the beginning of a description we are making abstractions and so working with models. But more abstractions and so modelling are made to describe some physical reality. For instance we can consider the simple model of Earth as a round object with mass and consider just the center of mass to obtain its orbit around the Sun as another object with mass at its center applying the gravitational laws between objects with mass. Now if we want more accuracy in the trajectory of Earth we must consider other model with the gravitational effects of the moon and the other planets and so another model of the "reality" takes place. A problem arises if some model gives a description that doesn't match with some direct experimental observation of something. Well, in this case the model would need to be improved or may be another model would be needed. Physics is always involved in finding the right models to describe physical realities and that always implies the look for the truth.

To all of you, just forget it. I will not post anything else. 🤷‍♂️

I edited my previous post. Just take a look. You will get satisfied now.

No I'm not. The question is if the moderators are satisfied with your responses. Thinking better. No one expresses to be good to analyze even just the beginning of a new possible theory. I think is not a good idea then. I think you would prefer to wait how Physics Science evolves to discuss the things. I also think now that certain members will make the discussion too hard to follow. Waste of time. Thanks for your comments. Is not my intention to just stay bothering other ones and I don't want to get bored too. May be on other opportunity in a far future, who knows...

Not necessary here. I already gave a good initial description of it while asking moderators' approbation and I'm already getting your responses here.

To present a theory in just a paragraph? I don't understand...

Why is dark matter being looking for so hard then? As far as I know the galaxies' dynamics observations don't match with the relativistic predictions. I'm asking for the possibility to present a new possible theory in the Speculations forum. If something goes wrong the thread could be moved to trash or just deleted.

I think that the premise is questionable since, just for instance, RT requires dark matter to exist while is something that haven't been demonstrated to exist. So is possible that a new theory could surge. I would like to present my approach but if you think is not appropriated I will not do it.

I would like to move to which would be my next step and I have some questions to the moderators of the forum. As I said, if the actual Force Law would be F = ma generalized for variable mass, Relativity Theory would not handle that and an alternative would be needed. I worked hard on a possible new theory and developed a manuscript of 112 pages to present what would be just the start point of it. The description is not suitable to be presented in just an article of a journal with peer review. I have already sent the manuscript to the secretary of the most prestigious universities in the area of Physics for possible evaluation but I would like to also share my approach here in the forum. My intention is to post a thread to discuss just the beginning of the theory, a couple of short sections but also uploading the manuscript (pdf of 1Mb) for those who would like to have at this time a complete picture of where the things could go now. A big problem the theory has is that it would be the worst possible theory. As I say in the manuscript: "The proposed new theory is consistent with Classical Physics, Photon’s Physics, the Einstein E=mc2 formula, Planck E=hυ formula and the De Broglie relation, although some corrections must be made. It disagrees with Einstein’s Relativity Theory, the “Quantum Physics” based on the “Wave Mechanics Theory”, the Electromagnetic Wave Theory, the Rutherford-Bohr model of the atom and today’s subatomic “Standard Model” based on the Quarks Theory." To give a brief description of the theory I have a quote: "Classical Physics is coming back reloaded! With a new definition for the electric and magnetic fields and the right structure for the elementary particles it really works now." The manuscript could be updated times to times and so I would like to also provide the link of a site of my own for any one be able to stay up to date. I think I could do this here in the Speculations Forum without violating any rule of the forum but I would need the approbation of the moderators of the forum for if something is not as I think it is. Any advice would be welcome.

So, even for rockets with variable mass the equation holds and it actually works in practice. Just a question remains: if it must be generalized or not. "Just" one big problem: Relativity Theory falls. It cannot handle that. There's no other case where it would not hold, I think. So, what's next? To discuss other possible implications of the Equation of Force be F = ma and not F = dp/dt or to look for an alternative to Relativity Theory? Or both? These are the subjects now. May be new threads must rise, I don't know...