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Feb26-12, 10:55 AM
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Quote Quote by Moataz View Post
Also, my book says that this formula only works in inertial frames.

[tex]\Delta \tau = \int \sqrt[]{1-v^2}dt ; v=speed[/tex]

Bu that does not make sense because v is in terms of t and it is supposed to change over time which means there must be acceleration!?
"Inertial frame" means the observer is not accelerating. It doesn't mean that the object being observed can't accelerate.