The discussion centers on the behavior of light in an accelerating elevator, specifically addressing the time it takes for light to travel from the top to the bottom of the elevator. Participants clarify that in an inertial frame, the speed of light remains constant, but in a non-inertial frame, such as the accelerating elevator, the measurements of time and length can vary. The conversation emphasizes the necessity of selecting appropriate coordinate systems, such as Rindler coordinates, to accurately analyze the situation. Ultimately, the participants conclude that light cannot be treated the same way as a non-relativistic object like a ball.
PREREQUISITESPhysicists, students of relativity, and anyone interested in the dynamics of light in non-inertial frames will benefit from this discussion.
In an inertial frame, yes.John Mcrain said:Bottom moving toward light,so time would be smaller then t=2m/c?
How explain smaller t, c increase(impossible), elevator become shorter then 2m ?Dale said:In an inertial frame, yes.
The speed of light is only invariant in inertial frames of reference. It can differ in other classes of frame.John Mcrain said:How explain smaller t, c increase(impossible), elevator become shorter then 2m ?
Obviously, the explanation is that the elevator is moving in the inertial frame. You already gave that explanation in your OP so I am not sure why you seem to be ignoring your own statements now.John Mcrain said:How explain smaller t, c increase(impossible), elevator become shorter then 2m ?
Before you ask any questions about the frame of the elevator you will need to define what you mean. Common choices would be Kottler Moeller, Rindler, or Lass coordinates.John Mcrain said:In frame of elevator
So I cant use same formulas as instead light is ball?Dale said:Obviously, the explanation is that the elevator is moving in the inertial frame. You already gave that explanation in your OP so I am not sure why you seem to be ignoring your own statements now.
Before you ask any questions about the frame of the elevator you will need to define what you mean. Common choices would be Kottler Moeller, Rindler, or Lass coordinates.
See https://en.m.wikipedia.org/wiki/Rindler_coordinates
Once you choose the coordinates you choose to represent the frame of the elevator then the remainder of your questions can be answered
light can be faster then c in non inertial frame?Ibix said:The speed of light is only invariant in inertial frames of reference. It can differ in other classes of frame.
I'm not sure who is measuring what in your scenario, so it's difficult to know how to answer exactly. But note that, as measured in an inertial frame, the rate of a clock in the lift is varying, as is the length of the lift. This will have consequences for the speed of light as measured by an observer in the lift.
Not if you want it to be relativistically correct. Of course, if you just want a rough approximation then that would be fine.John Mcrain said:So I cant use same formulas as instead light is ball?
YesJohn Mcrain said:light can be faster then c in non inertial frame?
You still have to choose your coordinates for that.John Mcrain said:Men in elevator meassure with stopwatch how long take the light to hit the flor.
Ball in my video has a=10m/s2, what is acceleration of light?Dale said:Of course, if you just want a rough approximation then that would be fine.
The problem is not the value of ##a##. You have to choose a coordinate system for the accelerated frame to get relativistically accurate results.John Mcrain said:Ball in my video has a=10m/s2, what acceleration I must use for light?
I ask for non relativistic case, case where I use formula as in my video with ballDale said:The problem is not the value of ##a##. You have to choose a coordinate system for the accelerated frame to get relativistically accurate results.
Why are you so resistant to making this choice?
The problem with that is that you don't have a static situation. If the proper acceleration doesn't vary along the height of the lift then the length of the lift is varying in its own rest frame. And you still need to choose what coordinates to work in, because you can't avoid relativity when you are asking about light.John Mcrain said:I ask for non relativistic case, case where I use formula as in my video with ball
That mean I cant use formula from my video with ball.Ibix said:And you still need to choose what coordinates to work in, because you can't avoid relativity when you are asking about light.
For a non relativistic case you can use the approach in the video, but that would be best in a different sub forum. The relativity sub forum is for relativityJohn Mcrain said:I ask for non relativistic case, case where I use formula as in my video with ball
To be fair, this is in Classical. But it's relativity anyway if we need to discuss light in accelerating frames.Dale said:The relativity sub forum is for relativity
Oops, that’s embarrassing.Ibix said:To be fair, this is in Classical. But it's relativity anyway if we need to discuss light in accelerating frames.
How can I use this approach for light, if I dont know what is acceleration of light?Dale said:For a non relativistic case you can use the approach in the video,
I didnt know when I write my first post that belong to relativity..I think I wont go to relativity forum for now, it is too complicated..Dale said:@John Mcrain please decide if you want to discuss balls or light. If you want to discuss light then I will move this to the relativity forum. If you want to discuss balls then I will close this thread and you can start a new one focused on balls.
You cannot. Balls are non relativistic. Light is the most relativistic thing there is.John Mcrain said:How can I use this approach for light
Sounds good. I will close the thread then. When you are ready to discuss light please post in the relativity sub forum.John Mcrain said:I think I wont go to relativity forum for now, it is too complicated..
And with ball answer is in my video...