Recent content by GerryB

Well I agree with your definition of invariance in STR, but I think invariance has meanings beyond that. Since gallean transformations are contained within STR, but whose effects are negligible at the speeds of an average train, we can still use the old formulas. In classical galilean...

Yes we agree on the importance of the meanings of words, but we seem to disagree on the meaning of invariance as it applies to sound, which is a key aspect of my question. So it seems pretty unresolvable.

The ink on paper, the symbols, may not be important, but the meanings behind those symbols is of life and death importance. If the service engine light comes on in your car, the little light cannot harm you, but if you disregard the warning, you will have to suffer the consequence of having to...

I do science, and I write poetry, so words are very important to me. In the examples you mentioned, certainly different branches of science or mathematics may, by happenstance, use the same symbol to describe very different properties. But in physics I would expect that there are some very...

Now we have come back around to my original question. What properties do sound waves and light waves share such that scientists use the symbol c to represent the wave velocity of both?

Well Peterdonis, I first read this in Tipler Physics, but I have seen it in many other places as well, as I mentioned above: http://en.wikipedia.org/wiki/Doppler_effect

Certainly these formulas are with respect to the medium. On a windless day, the medium is connected to the stationary observer, which is connected to the stationary earth. So if the medium is moving towrds the source, then the platform and the Earth are also moving towards the stationary...

As my buddy once said while drinking some beers at a local bar, "Mathematics is not Reality." The galilean transformation offers up two different values for one and the same particle (velocity, position, etc.) Which value is the truth, which is the REAL value?

In any science text I have read on the classical Doppler effect, there is one set of formulas for the source approachig the receiver, or moving away from the receiver. There is another set of formulas for the receiver approaching the source, or moving away from the source. And they are...

Let us say that the train and whistle (source) are approaching the stationary platform observer (receiver). The classical Doppler formula which the platform observer would use is: ƒ = [c / (c + vs)]ƒ0 If the platform and the non-walking observer (as well as the entire earth) were...

Certainly I am talking about the classical principle of relativity and how that relates to Einstein STR. The 30 mph is certainly a reasonable value for producing results in this experiment The philosophical problem is, to which reference frame does the still air belong, in an intuitive sense...

Well Simon, we seem to be moving from physics into philosophy. Are you saying that the train observer and the platform observer measure different speeds for the sound wave from the train whistle? Well Nugatory, creating wind on a "windless day" seems to be more of a philosophical problem than...

The Earth drags a several miles thick layer of atmosphere along with it as it hurtles through the galaxy. So, the air / medium moves with the earth, fortunately for us. Let us assume that air near the surface of the earth, in the vicinity of the train, behaves uniformly in all directions...

Ah Simon, this is what I am looking for, to which equations can both light and sound be applied? At the slow speeds of sound waves, Special Theory relativistic effects should be negligible.

We may have to agree to disagree. The speed of the sound is independent of the speed of the source of the emitter of the the wave, like light. When the source and receiver are traveling in tandem, and their motion is disconnected from the medium, then I am supposing that the MM formula would...