Special Relativity - relative motion of two bars

[John Sellars]

Hi, I'm stucked in this exercise. I don't know how to proceed. Any hints I appreciate it.Two bars of the same proper length L, moves in the same way on the x axis. In the referential of one of the bars the time interval between the events, when the extremity right of one bar and the extremity left of other bar is equal to to Δt. Find the relative velocity of the the two.

 

[mfb]

How can they have a nonzero relative velocity if they move in the same way?

In the referential of one of the bars the time interval between the events, when the extremity right of one bar and the extremity left of other bar is equal to to Δt.

The grammar in that sentence looks broken.

Find how long the second bar is in the frame of the first bar (as function of the velocity v). Then determine how that length, the velocity and Δt are related. That should lead to some equation for the velocity that you can solve.

 

[Dale]

@John Sellars you must show your work on this site. What have you tried so far.

 

[robphy]

Someone else is asking this question:
https://physics.stackexchange.com/questions/590423/special-relativity-relative-motion-of-two-objects