studiot

So can you articulate a complete question now? One further question. Are you familiar with the idea of stable unstable and metastable equilibrium ?

Gravity plays a huge part in the activity of gymnasts, skaters, swimmers and many other athletes. One of the most important issues is the effect of centre of gravity on balance. Is this the sort of thing you want to talk about?

I have been trying to play down the mathematics since I know you are not big on that. But once you are talking about rotation and deformable bodies you are into the mechanics of materials ie shear stress, which is a rotation. Such rotations are not connected with the COG of the body. Further rotational mechanics arises in the dynamics of fluids, again the centre of gravity does not play a large part in this. So some examples from you of the situations you wish to examine would be useful. You continue to use the term centre of gravity and I tried to explain the difference between the centres of mass and gravity. I hope you understood it. COGs are only important in a gravitational field, and particularly when gravity is the main force acting. Ask if you don't.

Here is a thought. There are many mathematical ways of representing or describing any particular physical phenomenon. But there is only one chain of physical reasoning that leads to it and the one physical phenomenon of interest. All valid mathematical representations should end in (predict) the same physical result. Since you want a test physical phenomenon to predict, please predict the value of the Lamb shift.

There are three possible sets of axes connected with rotations. Each of these sets can be variously oriented with respect to the others, and also offset by a distance. 1) We have the general axes in which you are working, say two horizontal, and a vertical one. Or up/ down ; forward/back ; left/right. 2) Then we have what joigus was talking about which are called the axes of inertia. The principal axes of inertia are obtained when the 'cross products of inertia' are zero and you are left only with moments of inertia and the radius of gyration. 3) The so called Euler axes which are an orthogonal set (mutually perpendicular) about which we apply three separate torques. They are probably what MigL was talking about. I have posted this experiment before. Take a brick shaped object such as a brick, book, matchbox empty chocolate box etc. Imagine an axis of rotation through each of the three pairs of opposite faces. So they correspond to pitch, roll and yaw in aviation or boating parlance. In turn, toss the object into the air giving it a spin about one of the axes. You will find that the spin is stable abot two axes and unstable about the third.

Here are two very easy examples. Go to the door of the room you are in Take the handle. Open and close the Door. The door rotates about a (hopefully vertical) axis through the hinges. You are the external agent and apply a force at the handle. But where is the centre of gravity of the door? Somewhere in the middle of the door. Take a sheet of paper and a drawing pin. Pin the paper loosely to a pinboard by the top left corner so the paper swing round under its own weight. Now change the pin to the bottom right corner. Once again centre of gravity is in the meiddle of the paper, but The axis of rotation (the pin) is somewhere else and is now horizontal.

Yes you are seriously mistaken. Just think of a solid heavy weight swung round on a long string. The centre of rotation is the hand holding the other end of the string The centre of mass is somewhere inside the heavy weight. Just to be precise, "the centre of gravity is on the line through a body leading to the centre of the Earth, that the weight of that body appears to act." And the axis of rotation is determined mostly by external agencies. Might be better to phrase this The centre of gravity or centre of mass of a body may change if the configuration of the parts of the body changes. And the axis of rotation is determined mostly by external agencies.

Polio is an RNA virus; more than one vaccine has been developed for it.

I think my brother had a kit, but I don't know all the details. The school project definitely did process their own grinding and polishing (I did not participate).

Cost? My brother (a Mechanical Engineer) made one a few years back for his own interest, in addition to buying one. I remember my secondary school in the 1960s also had a collective project to do this, run by the Arts teacher who had amateur astronomy as a hobby.

Thank you for posting this information and the video. +1 Hopefully it gives a guide to your thinking. But the video also shows exactly what I said. You have missed out a term from the simplest form of the Dirac equation. At about two and a half minutes the video introduces an equation which includes a Ψ. This is maintained right through the subsequent development from Schrodinger to Klein Gordon to Dirac. It is discussed in detail at 10 minutes and appears in the finale display of the Diract equation at fifteen and a half minutes. So you are missing this. BTW the video is not bad but carefully emphasises it is the Dirac equation for an isolated particle only. It doesn't tell you but this is because it is developed from the original energy statement which only accounts for kinetic energy it is deficient. The fun arrives when you include a potential term or terms (as Dirac did). I also said your posting graphs on a 'sheet of paper' along with the stament that the blue squiggles are real and the gold imaginary (ie a single plane) amounts to saying that you are claiming the imaginary and real axes are one and the same thing. The gold squiggles can only appear on the same plane as the blue at isolated points since the imaginary axis must, of necessity, be orthogonal to the two real ones. Sadly your video also made this mistake, although other than that it makes a creditable fist of a short introduction to Dirac.

One other thing (english word parameter) is which way round the Sun the planets travel Venus goes the other way form Earth. I'm sorry I didn't catch your language, so this reference is in English. But Wikipedia has other language versions. https://en.wikipedia.org/wiki/Retrograde_and_prograde_motion

https://phys.org/news/2019-09-three-photon-color-entangled-state.html

And I'm pretty sure you don't read what others are saying to you. I told you that there were terms not included (missing from) the equation you posted as the Dirac equation. Your response was that you had missed some overbars from your terms. So I asked you how do you put overbars over terms that are missing? And you respond with a personal insult about my mathematics skills. Once again proof positive that you are not reading what is said to you. I posted said quote from you post immediately after my statement. Can you not read your own writing?

What exactly does someone who claims to understand both higher quantum theory and higher relativity theory not understand about the reference to "my last post" ? And why did you not post the correct Dirac Equation? How on Earth can you put bars over missing terms and variables? But then this is from the stable that made the astounding claim that the imaginary axis coincides with a real one.

That's exactly what the Dirac equation uses. Not exactly, no. You have missed out some very important terms and variables. And since you once again can't be bothered to acknowledge my offer of help (as in my last post), I don't feel very inclined to do so.

In his book Alven's protege, Lerner, documents quite the reverse trend. https://books.google.co.uk/books/about/The_Big_Bang_Never_Happened.html?id=RMa5uCzz_ZkC&source=kp_book_description&redir_esc=y Some of the physics is a bit dated now but the social backgrund is still valid. When I was young, my family moved about a lot. So I attended primary scchools in England and secondary in England but also in France and West Germany. Even at the time I was struck by the enormous differences between the systems, both regionally in England and between the three countries. In particular one thing stood out in Science teaching. The French textbooks hardly ever mentioned a German scientist and the German ones a French Scientist. At least the English ones were pretty even handed on the principal scientists from all nations. Again I come back to my comment that it depends upon your national TV structure. The BBC has long produced and broadcast (both radio and TV and today over the net) educational material for schools from infants up to senior secondary level. The material is designed to fit in with and produce lessons for whatever passed for a national curriculum at the time. In some instance they were national leaders, for instance 'the BBC computer'. In the present covid crisis they have stepped up to the plate and increased this output to help reach children stuck at home when they should be at school. Commercial channels have also a history of high quality output, but in much lower quantity since audiences are smaller than for some other types of programme.

Yes I note that you have assumed not claimed a mathematical structure for the universe the Universe , and further proposed a mathematical equality to base you analysis on. But you do seem to claim yours is the only rational explanation. Then you also give us an example of competing rational explanations for another phenomenon. So let us look at your equality dispassionately. 0=U. Different (but not incompatible) things can be deduced (rationally) from this statement in Mathematics and in Physics. In Physics the equality could suggest a conservation Law; indeed you want to use it in that way. But here is the story of another very fundamental conservation Law, which can also be modelled by equating something to zero. Conservation of momentum. [math]\sum {{m_h}} = 0[/math] Consider directing the stream of water from a fire hose horizontally at a wall. As the stream travels through the intervening air it has a horizontal momentum. When it strikes the wall the horizontal momentum disappears. What happened to conservation? Is it violated, it seems to be? Further the stream spreads out vertically over the wall, generating vertical momentum form zero! Physics supplies the rational answer. It is not magic, there is another agent missing from the conservation law in this case.

Just a guess but I have been wondering if John's method of analysis is a form of curve fitting given the range of possible solutions to the wave equation and his reluctance to discuss the mathematics of it.

BBC again. Did you see the Walking with Dinosaurs series? There was also a programme where they discussed the amking of and it would appear that the CGI team faced the fact that no one really knew how dinosaurs locomoted. So the studied it scientifically and some very interesting new bioscience came out of that, which was described. I remember from school we had the Unilever chemistry pamphlets. The ones on surface chemistry, and the one on glycerides I remember well and the one on quantum bonding had a film with it that was especially good. Excellent point.

Entanglement is complicated by the fact that there can be degrees of entanglement. Full entanglement is called maximal entanglement, Partial entanglement results in various special states, for instance with photons the colour may be entangled for 3 photons, resulting in what is called the W state. https://en.wikipedia.org/wiki/W_state

I hope this is not an expression of the all too common fallacy that all you have to do to teach something is to know your subject.

https://www.bbc.co.uk/ideas/videos/why-iq-is-not-the-same-as-intelligence/p08c6nd8

I suppose it also depends upon the quality of TV where you are. Here, some are really good, the BBC has produced some first classones eg in Earth Science with a 'textbook' to go with it, now in its second edition. But I agree there are some 'handwavy' presenters as well. Commercial stations are less likely to expend the resources necessary as the audiences are smaller than say the 'soaps' But I have noticed that the soaps (I have never been into them) have become more like the gangster movies of 20/30+ years ago.

What's black and comes rushing out of the ground shouting knickers knickers knickers ? What's black and comes rushing out of the ground shouting panties panties panties ?