HI, I've been mulling over the derivation of the Lorentz factor gamma in my head for some time now & had worried about it a bit.(adsbygoogle = window.adsbygoogle || []).push({});

I've now discovered that what was bothering me was something called "frame-jumping".

This is where you use the Pythagorean Theorem to derive Gamma.

If you're unsure of what I'm talking about I'll point you to a video showing the derivation, it's only around a minute long, watch at time 12:45 to 13:30 or so and you'll see what I'm on about.

http://video.google.com/videoplay?docid=-6328514962912264988# [Broken]

So

I'd just like to hear from an expert WHY every standard college level intro textbook

uses an incorrect derivation of the Lorentz Transforms...? If this is true.

Also, A VERY IMPORTANT THING I HOPE YOU'LL BE ABLE TO ANSWER.

In Kleppner & Kolenkow's Introduction to Mechanics will they use this derivation?

Thanks so much for any comments...

BTW: I found out about this thing called frame jumping from an online post,

here is the link if you're curious,

http://www.physforum.com/index.php?showtopic=21780

If you don't want to mull through the page I'll quote one important part of it,

the saw tooth thing is a reference to the hypotenuse line of motion that the

photon traveling perpendicular to the velocity.

One last thing: the "saw-tooth" path of the light beam in the observer frame is a CONSEQUENCE of the Lorentz transforms, explained later in the Einstein paper under the "aberration " (paragraph 7). Interestingly enough, I have never seen aberration mentioned as the reason for the saw-tooth path in any textbook. It is the correct reason, nevertheless. Since the equation of aberration is BASED on the Lorentz transforms and they are BASED on "gamma", you cannot use this type of reasoning in order to derive....gammma. So, your approach leads to a dead end. On the positive side, you now have the means of getting educated on the subject. And Einstein did a superb job, enjoy :-)

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# Frame-Jumping & Incorrect Gamma Derivations Aplenty

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