Physics 62 Special Relativity (14 of 43) Einstein's Postulate of Special Relativity - 2A

In this video I will explain Einstein's postulate of special relativity – 2nd Postulate: 2A.

Next video in the Special Relativity series can be seen at:

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Can we say the Einstein postulated the special theory of relativity and Lorentz formulated it ?

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Did Lorentz derive his transformation before Einstein discovers his theory of relativity, while Galilean derived his long before Newton?

[chavab]

Michel, you once responded to one of my comments with great empathy trying to explain some concepts. PLEASE take a look at this video of yours to see how misleading it is. Below is my comment from one year ago, when I first viewed your full series (43 videos). EM waves, like other waves, do NOT act like mass in summing with the velocity of the emitter. It is NOT analogous to a baseball thrown from a car. If you imagine the shortest pulse of a light wave (one full cycle) being briefly emitted from a vehicle, the velocity is a CONSTANT. For sound, it is 340 m/s in air. For light and other EM, it is "c". The only thing that matters is the position of the emitter when the pulse is emitted. Then you calculate D = R X T or R = D/T or T = D/R to get all variables. At relativistic velocities, the time and distance components are changed. This mistake is propagated frequently in physics lectures and books. It is really a simple concept. Stick to mass to get any understanding of how gamma affects time and distance. PLEASE!!

[chavab]

This video gets to the heart of my confusion about SR. I tried to revisit the path of physics from Galileo to Einstein and early in my journey I considered what sound would do in the exact situation described in this video. Sound emitter from a moving source would also travel at 340 m/s to an observer directly in its path of travel. So, it does not surprise me any more that light waves do the same. How do we integrate wave-type things versus mass type things (like the missile from video 7/43)? BTW, you are a GREAT teacher)

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LIFE SAVER !!! PHYSICS 1, 2 AND 3 THANK YOU !