Galilean transformation of ordinary waves
BARTON ZWIEBACH: Do normal wave analysis to demonstrate that indeed these things should not quite happen. So for that, so ordinary waves and Galilean transformations. So when you have a wave, as you've probably have seen many times before, the key object in the wave is something called the phaze of the wave. Phaze, the phaze. And it's controlled by this quantity kx minus omega t. k being the wave number, omega being the angular frequency and we spoke about. And the wave may be sine of that phaze or cosine of that phaze or a linear combination of sines and cosines, or E to this wave, any of those things could be your wave. And whenever you have such a wave, what we say is that the phaze of this wave is a Galilean invariant. Invariant. What it means is that two people looking at this wave, and they look at the point on this wave, both people will agree on the value of the phaze, because basically, the reality of the wave is based on the phaze, and if you have, for e...