Re: [Phys-L] Fwd: relativistic acceleration of an extended object

[John Mallinckrodt <ajm@cpp.edu>]

On Nov 10, 2014, at 6:44 AM, Bob Sciamanda wrote:

> Perhaps it should be noted that to an observer at rest in frame B the 
> travelling clocks were "always" out of synchronization - even when they 
> began their trips, at rest in frame A.

That's right.  Moreover, in frame B, the specific amounts by which they are out of synch is the same before and after the acceleration phase.  Indeed, this is true in any inertial frame because the elapsed times displayed on each clock during its own acceleration are identical.

The differences are that, in inertial frames other than A, the accelerations occur during different time periods so 

1. the clocks do not maintain their relative "out of synchness" during the acceleration phase and

2. the spacings are different before and after the acceleration phase.

John Mallinckrodt
Cal Poly Pomona
johnmallinckrodt.com