- #1

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https://www.physicsforums.com/showthread.php?t=67782

cd

(p.s. i am only in teh beginning class of geometry)

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- Thread starter cd27
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https://www.physicsforums.com/showthread.php?t=67782

cd

(p.s. i am only in teh beginning class of geometry)

- #2

Doc Al

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- #3

jtbell

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cd27, after a quick read of your original thread, it seems to me you're confused about "difference" versus "factor". All this is, is that whereas you calculated the **difference** [itex]\Delta t - \Delta t^\prime[/itex], people generally use the **ratio** [itex]\Delta t / \Delta t^\prime[/itex] when talking about time dilation:

[tex]\Delta t = \frac {\Delta t^\prime}{\sqrt{1 - v^2 / c^2}}[/tex]

[tex]\frac {\Delta t}{\Delta t^\prime} = \frac {1}{\sqrt{1 - v^2 / c^2}}[/tex]

This quantity comes up over and over again in relativity (not just in time dilation), so we call it [itex]\gamma[/itex] for short:

[tex]\gamma = \frac {1}{\sqrt{1 - v^2 / c^2}}[/tex]

so that

[tex]\frac {\Delta t}{\Delta t^\prime} = \gamma[/tex]

or

[tex]\Delta t = \gamma \Delta t^\prime[/tex]

We call [itex]\gamma[/itex] a**factor** because a factor is what you **multiply** something by, in order to get something else.

[tex]\Delta t = \frac {\Delta t^\prime}{\sqrt{1 - v^2 / c^2}}[/tex]

[tex]\frac {\Delta t}{\Delta t^\prime} = \frac {1}{\sqrt{1 - v^2 / c^2}}[/tex]

This quantity comes up over and over again in relativity (not just in time dilation), so we call it [itex]\gamma[/itex] for short:

[tex]\gamma = \frac {1}{\sqrt{1 - v^2 / c^2}}[/tex]

so that

[tex]\frac {\Delta t}{\Delta t^\prime} = \gamma[/tex]

or

[tex]\Delta t = \gamma \Delta t^\prime[/tex]

We call [itex]\gamma[/itex] a

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- #4

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interseting...now can ask "why" they use ratio rather than difference?

cd

cd

- #5

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jtbell said:[tex]\frac {\Delta t}{\Delta t^\prime} = \gamma[/tex]

does this mean divide? so i divide my originl time by the T' to get this "factor"?

also, so i get a factor (the purpose of the factor) is so that i can multiply it to something else-what other formulas (for some reason or another) would i multiply this to and why use a factor to do it?

sorry if i ask so many questions, i just hate mathematics, and it's not b/c it's a hard subject (it's actually rather simple-but like i said in my other thread, you don't know what you haven't learned), i just can't stand it when my teacher tells me to "do this" or gives me some type of formula without telling me

i understand things much better when i understand why they are done. plus, i'm fascinated with understanding things. eh...it's just something i like to do.

cd

- #6

jtbell

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In relativity, [itex]\gamma[/itex] turns up in formulas for length contraction, time dilation, relativistic momentum and energy, the Lorentz transformation, etc. As for

- #7

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lol, i know a bit about physics as well.

cd

cd

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