I thought I understood SR's time dilation and length contraction. But after reading the section on "simultameity" in Tipler I am just as confused as before. Here is my source of confusion.(adsbygoogle = window.adsbygoogle || []).push({});

[A] Muon Decay:

S frame = frame of the earth; S' frame = frame of the muon

A muon falls to earth at a speed of 0.998c ('c' of course is the speed of light). In its own frame it's lifetime is 2.0 μs, and the distance it travels is only 600 m.

But, in the earth's frame, the speed measured is the same, but the length is 9000 m and the lifetime is 30 μs. This makes perfect sense to me since, L = γL' and the distance (L' < L) is contracted for the moving particle.

Rocket Ship:

A rocket ship flies past 2 points, A and B in S (the earth's frame) and is measured to be a length, L, when the front is over the point B and the back is over the point A. Tipler's explanation is that this is the contracted length of the ship in S', namely: L = L'/γ. Therefore the ship's length in S' is L' = γL. This means that the moving ship's length is longer than that measured in the earth's frame, or, L ' > L. And this is a direct contradiction to length contraction in [A]!

I know I the truth is that I don't understand this so I came here for an answer.

Thanks in advance!

-LD

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# Homework Help: Length Contraction, which way is it?

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