9277 #94

Maxwells_Demon
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9277 #94

Postby Maxwells_Demon » Tue Sep 23, 2008 7:15 am

http://grephysics.net/ans/9277/94

If gamma = 5/4, then beta does not equal 3/4. How is C the answer? When gamma = 5/4, then beta should be 3/5, NOT 3/4. So I thought the answer was E... Has anyone run into this before? Maybe I'm an idiot, though

-Maxwell's Demon

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Unnatural Log
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Joined: Fri Aug 15, 2008 4:07 pm

Re: 9277 #94

Postby Unnatural Log » Tue Sep 23, 2008 11:33 am

Remember that the gamma applies distributively in a Lorentz transform, like this:

x' = gamma(x - vt)
t' = gamma(t - vx/c^2)

So you're right that beta = 3/5, but the coeffcient of t (in x') and the coefficient of x (in t') is not beta, but rather beta multiplied by gamma, ie 3/5 x 5/4 = 3/4.

I think that's it. :)




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