Acceleration and time question

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if two objects were accelerating on parallel lines, would it appear to an observer on one object that the distance apart was increasing, due to special relativity?
 
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Hi ErnieDouglas! Welcome to PF! :smile:
ErnieDouglas said:
if two objects were accelerating on parallel lines, would it appear to an observer on one object that the distance apart was increasing, due to special relativity?

If they're "level" with each other, definitely no …

"sideways" length is never altered.

If they're not level, it depends how the accelerations are related …

does a stationary observer regard one as always a constant distance ahead of the other (in which case, yes), or are they "rigidly" connected, like the front and back of a train (in which case, no)?
 

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