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by Remundo » 20/06/10, 19:51

Hi Dedeleco

"almost identical" ... a little daring. 8)

Coriolis only manifests if there is a relative velocity in the Earth's frame of reference, and is proportional to the angular velocity of the earth.

Centrifuge manifests itself all the time and is proportional to the square of the angular velocity.

Coriolis is orthogonal to speed, while centrifugal is always radial to the Earth's axis of rotation.

3 big differences, if not for the rest, we can see it like that.

Unfortunately, without math, the concepts of inertial forces are not precise.

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by sen-no-sen » 25/06/11, 18:11

An interesting article on Louis Michaud's AVE concept (in English):

http://memagazine.asme.org/Articles/2011/April/Skys_Limit.cfm
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by dedeleco » 25/06/11, 19:05

"almost identical" ... a little daring


The origin is the fact that without forces we go straight et on earth we turn at 2000Km / h at the equator without realising it !!
So all these forces have the same cause: resist the inertia that would make us go straight, to make us turn while staying on earth on its surface !!!

The rest is a mathematical description with historical memories !!

The Coriolis force is the force which tends to make us keep our speed of 2000Km / h of rotation, when we move from the equator to the poles where it becomes zero, just like the centrifugal force in a turn tends to make us continue straight instead of turning into a car or a bicycle.

This simple argument allows us to find the meaning of these forces and to avoid making the wrong sense, in particular the direction of the cyclones which tend to keep their intrinsic speed of movement of 2000Km / h in the winds approaching the poles, this without any calculations.

So we can understand without formulas, which then become a simple mathematical exercise, instead of drowning people in calculations that are not the physical essentials.

The gyroscopic effects are similar, for a wheel (of a bicycle, for example) whose axis is rotated with a perpendicular torque, if we consider the change in the speed of an element of the wheel, without calculations.


In France there is a tendency to put mathematical means well before the bases of understanding !!
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by Remundo » 25/06/11, 19:43

Physics without math is analogous to an automobile without direction ... It follows its intuition ... :P

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by dedeleco » 26/06/11, 19:00

Physics without math is analogous to an automobile without direction ... It follows its intuition.


No, it is the opposite, we can do a lot of calculations that do not correspond to reality, so, as I have seen sometimes, 30 pages of false and unnecessary calculations !!

Math without physics is analogous to a car without direction ... It goes out of the way with false math which does not describe reality ... !!

It's great fun to say to a mathematician: your thirty pages of calculation have errors, because the result does not respect the laws of simple physics and to see it working one month on its thirty pages to come back with the calculations corrected for errors !!!!

I had a famous teacher, who was terrified to see his engineering students think and run into equations before I even started.
He was sorry because it is a disease of French teaching to believe that we understand better with lots of complicated equations, often less general than physical understanding !!


It is even a facility, the equations think for you, instead of understanding without equation before.

In a mathematical calculation, we no longer understand what the calculation does, exactly as with a computer simulation, we understand nothing about the program's hypotheses which can sometimes be very false !!

In addition, for the same physics, there are often several different mathematical demonstrations and formulations.
For complex cases, we are forced to make approximations that only physics can justify.

So it is fundamental to understand and explain the phenomena with as few equations as possible, otherwise the equations understand for you, what you do not really understand !!!

Sorry to contradict on a point that was fundamental to my physics teacher and for me too !!


Maxwell with his great equations recognized that he was only translating Faraday's ideas and experiences, for example !!

Math is only a means, not an end in itself for the physicist.
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by sen-no-sen » 26/06/11, 19:49

Mathematics have their limits vis-à-vis reality.
For example if we divide 10 by 3 we get 3,33333 .... infinitely, except in practice if we divide a distance of 10 m for example, by 3, we will quickly arrive at a measurable limit ( distance from Planck).

Besides, this mathematical "logic" shows its limits with economics which does not take reality into account either.

If not to return to the AVE of Mr. Michaud, strongly a full-size demonstrators!
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by Christophe » 26/06/11, 23:22

sen-no-sen wrote:Mathematics have their limits vis-à-vis reality.
For example if we divide 10 by 3 we get 3,33333 .... infinitely, except in practice if we divide a distance of 10 m for example, by 3, we will quickly arrive at a measurable limit ( distance from Planck).


I think I see what you mean but your example is badly chosen: here it's just an approximation ...

We measure 3.33 m and we consider that 9.99 m = 10 m

What does Planck's length do with it? http://fr.wikipedia.org/wiki/Longueur_de_Planck
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by highfly-addict » 27/06/11, 01:41

Christophe wrote:...

What does Planck's length do with it? http://fr.wikipedia.org/wiki/Longueur_de_Planck


Extract of the link:
Consequently, Planck's length would be, in the current state of physics, the minimum length that it is possible to measure in a meaningful way.


...
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by dedeleco » 27/06/11, 17:16

Have you thought about the energy you need to measure this length ???
The energy of a whole supernova is not enough !!!

This is the whole mystery of our universe !!

Total HS!!
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by sen-no-sen » 28/06/11, 19:53

highflyaddict wrote:
Christophe wrote:...

What does Planck's length do with it? http://fr.wikipedia.org/wiki/Longueur_de_Planck


Extract of the link:
Consequently, Planck's length would be, in the current state of physics, the minimum length that it is possible to measure in a meaningful way.


...


Yes, that's what I was referring to.
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