Physics Help Forum Accelerating frames

 Special and General Relativity Special and General Relativity Physics Help Forum

 Aug 28th 2009, 04:50 AM #1 Junior Member   Join Date: Aug 2009 Posts: 27 Accelerating frames Are accelerating frames relative? That is, is the statement frame A is at rest while frame B accelerates rightward relative to A? the same thing as saying frame B is at rest while frame A accelerates leftward relative to B? My intuitive answer is no, because whoever is really will feel the affects of this like when on a roller coaster. Last edited by jamix; Aug 28th 2009 at 05:08 AM. Reason: remove material
 Aug 28th 2009, 08:14 AM #2 Physics Team   Join Date: Feb 2009 Posts: 1,425 I think you are right. The one in the accelerating frame will feel a force so the situation is not symmetric. However, it is not possible to distinguish between what is felt in an accelerating frame and what is felt due to a gravitational field. If you are in a closed space ship and you feel an increase in weight, this could be due to either the space ship accelerating, or an increase in the grav field.
 Aug 29th 2009, 12:47 AM #3 Junior Member   Join Date: Aug 2009 Posts: 27 For this one, I considered the Twin paradox as my arguement. In this question, in order to determine which twin is younger after they are re-united, you need to know which twin has accelerated into another frame.
 Sep 1st 2009, 10:52 AM #4 Junior Member   Join Date: Aug 2009 Posts: 27 More input Could others put in their input to the above? The reason I ask is because I've posted this question on another forum, and I'm getting contradictory answers. In fact I was told by none other than senior Fermi lab scientist and author Don Lincoln that I'm flat out wrong. Last edited by jamix; Sep 1st 2009 at 10:54 AM. Reason: changed something
 Sep 1st 2009, 11:25 AM #5 Physics Team     Join Date: Jul 2009 Posts: 310 Both observers experience some sort of relativistic effect, according to each other. __________________ "Dissent is the highest form of patriotism." - Thomas Jefferson. "Give me control of a nation's money and I care not who makes her laws." -Mayer Amschel Rothschild I study Mathematical Physics at the University of Waterloo. -DC
 Sep 1st 2009, 11:42 AM #6 Junior Member   Join Date: Aug 2009 Posts: 27 Any conclusion the moving twin (ie the one changing inertial frames) makes regarding his twin will have to be consistent that twins own observation once they re-unit (otherwise we really would have a paradox). In any case, I don't exactly see what you have said has to do with the original question.
Sep 1st 2009, 11:45 AM   #7
Physics Team

Join Date: Jul 2009
Posts: 310
 Special relativity does not claim that all observers are equivalent, only that all observers at rest in inertial reference frames are equivalent.
Twin paradox - Wikipedia, the free encyclopedia
__________________
"Dissent is the highest form of patriotism." - Thomas Jefferson.

"Give me control of a nation's money and I care not who makes her laws." -Mayer Amschel Rothschild

I study Mathematical Physics at the
University of Waterloo.

-DC

 Sep 1st 2009, 11:52 AM #8 Junior Member   Join Date: Aug 2009 Posts: 27 Yes that is correct, but weren't you referring to the TP when you made your post? I can't answer you if I don't know any specifics. Anyway the question that is being asked here, is Is acceleration relative?
 Sep 1st 2009, 11:56 AM #9 Physics Team     Join Date: Jul 2009 Posts: 310 Acceleration is not relative. __________________ "Dissent is the highest form of patriotism." - Thomas Jefferson. "Give me control of a nation's money and I care not who makes her laws." -Mayer Amschel Rothschild I study Mathematical Physics at the University of Waterloo. -DC
 Sep 1st 2009, 12:03 PM #10 Junior Member   Join Date: Aug 2009 Posts: 27 I see. Do I dare ask you why? In particular, if you are right, then why does one need to know which twin has changed inertial frames (ie accelerated) in order to determine who is younger in the typical TP question?

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