Recent content by wsellers

Thanks to both for your prompt replies! (I wasn't sure that all that was needed to do the calculation theoretically was the addition of velocities equation, so the post from Jorrie clarifies that.)

This is indirectly addressed in some posts but I can't find a direct answer to the following: consider moving frames A, B, and C (e.g., A, B, and C are 3 trains moving at different speeds on the same track; or A is a train, B is a person walking inside the train holding a tray, and C is a...

That does answer my questions--thank you very much for taking the time to respond.

Belated Reply Speaking just theoretically, could one say the following? 1. Consider a spherical impulse of light emitted from a point A at time t1, and the frame of reference that is "at rest" with respect to A. Wouldn't this frame of reference also be "at rest" with respect to ANY point...

Isn't this overstating things a bit? The observer in the middle of the moving car would have earlier seen the lightning flashes arrive at their eyeballs separated by a certain time delta [which, incidentally, I thought would have been 2dv/(c^2 - v^2) and not vd/c^2]. From this they would have...

This is another (hopefully not tiresome) question related to the relativity of simultaneity! Suppose you have the usual train situation, but with this addition: suspended from one end of the car to the other is a long roll of paper towels. At each end there is a vial of red dye. From an the...

I think I understand the relativity of simultaneity when the only "tool" one uses is light beams. What I can't tell is whether the logic holds up when other supplementary tools are available.

Hope I am not beating a dead horse, but something is still not clear to me. The observer standing on the embankment will (I think) predict that the light beams hit the center at different times while the mice will hit the center (which by now has moved quite a bit relative to that observer) at...

Just so I understand, does this mean then, in the case where (1) light rays go from each end of the car to the center, (2) robot mice go from each end to the center, and (3) each light ray and mouse movement is initiated by a lightning flash at either end of the car, THAT: the light rays do not...

Is it necessary to use light flashes? What if the observer uses a method that doesn't involve light flashes? To use a fanciful example, suppose the observer has two identical robot mice and sets them going in opposite directions from the midpoint. Regardless of the direction of the train...

Thanks very much! I wasn't aware of the headlight effect.

I don’t see that this question has been asked before and I am hoping the generous moderators of this forum will be able to answer it. Suppose you have the “standard” situation with the man M on the embankment and the woman W in the center of the moving train car. (The train has lots of...