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Tom Mattson said:Whether you are using Galilean relativity or SR, the equation is the same.
I can calculate the relative velocity between a light pulse and myself by measuring the following:
Event 1: Pulse Emitted
x1=Location of emitter on x-axis at time t1.
t1=Time of emission.
Event 2: Pulse Detected
x2=Location of detector on x-axis at time t2.
t2=Time of detection.
The speed of the pulse relative to me is then:
v=(x2-x1)/(t2-t1).
For light, this will always come out to be c. And as you can see, that result is not "built in" to the way we calculate relative speed. It is a simple, undeniable experimental fact.
Tom, you say it is not "built in", but consider the following;
Can you calculate the relative velocity between a moving car and yourself by measuring the following?
Event 1: Car Accelerated (Assume instantaneous acceleration to 60 Miles Per Hour)
x1=Location of car on x-axis at time t1.
t1=Time of acceleration.
Event 2: Car Detected
x2=Location of car on x-axis at time t2.
t2=Time of detection.
The speed of the car relative to you is then:
v=(x2-x1)/(t2-t1).
Can you alter the relative speed of the car while using this formula?
If not, then how is this formula the very definition of relative speed?
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