- #1
Hiero
- 322
- 68
Consider a rod oriented along and moving along the x direction at a speed v in frame A. In it's turn, frame A is moving at speed u in the y direction relative to frame B.
By my understanding of special relativity, the x component of the rod's velocity in frame B will be v/γu, and the y component is just u.
Also, the rod remains oriented along x (& same length) in frame B, because the ends are not displaced along the boost direction from A.
Also, in the rod's proper frame it is still oriented along x.As far as I can tell all of that is fine, but another perspective confuses me. I was thinking we should be able to look at frame B as being a single boost away from the rod's proper frame. This would be a boost with <x , y> velocity components being <v/γu , u>.
The point is, from the proper frame, we are boosting off at some angle with the rod's length, (not zero and not perpendicular) and as far as I can tell this necessarily causes the rod to be rotated when changing frames (whereas the analysis with an intermediate frame A told me that the rod remains along x).
Not sure where the problem lies. Thanks.
By my understanding of special relativity, the x component of the rod's velocity in frame B will be v/γu, and the y component is just u.
Also, the rod remains oriented along x (& same length) in frame B, because the ends are not displaced along the boost direction from A.
Also, in the rod's proper frame it is still oriented along x.As far as I can tell all of that is fine, but another perspective confuses me. I was thinking we should be able to look at frame B as being a single boost away from the rod's proper frame. This would be a boost with <x , y> velocity components being <v/γu , u>.
The point is, from the proper frame, we are boosting off at some angle with the rod's length, (not zero and not perpendicular) and as far as I can tell this necessarily causes the rod to be rotated when changing frames (whereas the analysis with an intermediate frame A told me that the rod remains along x).
Not sure where the problem lies. Thanks.