SR implies (or is interpreted as) the space contraction and time dilation depends on the relative velocity of the two reference frames.

B moves at .6 c relative to A.

B sees objects of known dimensions passing in the opposite direction appearing contracted to .8 their length.

A accelerates to .2 c in the direction opposite of B.

The relative speed of separation is now approximately .8 c.

This would require the contraction B sees to be approximately .6 c.

The objects moving past B do not speed up when A moves.

How do you explain this?

assuming the objects B is passing are "stationary" according to your scenario, B is still moving at .6c compared to them(A's acceleration doesnt change the speeds of B or the stationary objects, or their speed relative to each other), and therefore the contraction doesnt change. B is moving at .8 compared to A, so A might look more contracted.

 

ive never understood anything about relativity, but these are my logical assumptions based on what ive been told. sorry for any inaccuracies.

Also, not sure I've quite understood your thread I'm a little bit worn out...

 

K frame is stationary to an observer.

K'' is moving at 0.8c according to an observer in K'

K' is moving at 0.5c accoring to the observer in K

 

The velocity of K'' measured in K' also suffers a transformation it is not simply 0.8c+0.5c...

When Klaynos listed 3 ref frames it got clearer. That's why someone else

looking from a distance sees the things that are right under your nose.

Thanks