Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.
In Alan's frame, at exactly the same moment (t = 0) Beth passes him, two sparks shoot outwards from the tracks. Call those sparks events 1 and 2.
The location of spark 1 is at exactly x = +5m according to Alan, and the location of spark 2 is exactly x = -5m . You may find it useful to measure time in nanoseconds for this problem. Light takes 16.7 ns to travel 5 meters.
Beth's train is moving at v = 0.5c to the right. Can you calculate the times and locations of the two events, spark 1 and spark 2, in her reference frame?
Alan's frame Beth's frame
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x1 = x1' =
Spark 1
t1 =
t1' =
x2 = x2' =
Spark 2
t2 =
t2' =
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Copyright © Michael Richmond.
This work is licensed under a Creative Commons License.