- #1
wsellers
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This is indirectly addressed in some posts but I can't find a direct answer to the following: consider moving frames A, B, and C (e.g., A, B, and C are 3 trains moving at different speeds on the same track; or A is a train, B is a person walking inside the train holding a tray, and C is a wind-up toy moving along the tray; etc.). Now observers in each frame calculate the speed of the objects in the two other frames relative to them. Will these calculations always agree reciprocally--e.g., will a person in A calculate a speed for the motion of C that is the same (magnitude) as the speed calculated by a person in C for the motion of A? I believe the answer is "yes" but would like confirmation.