
010511, 10:11 PM #921

010511, 10:27 PM #922
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 3,595
Originally Posted by Motor Daddy
You aren't a physicist either, or much of a logician.
But, hey, since you can add and subtract, Einstein must have got it wrong . . . everyone knows how useless he was with math.

010511, 10:31 PM #923

010511, 10:35 PM #924
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 3,595
You go wrong when you assume that understanding how to add and subtract means you can understand special relativity.
Post #912 without even looking at it, is guaranteed to be a repeat of every other post you've made in this thread. I rest my case.

010511, 10:40 PM #925

010511, 10:52 PM #926
 Posts
 3,595
I can see that it's wrong, and I can explain why. So can more than a few other people.
You can't answer questions or accept that your logic is almost totally flawedyou still don't seem to understand things that you've said you do understand, for instance what a stationary frame is, what an observer is, and so on. Even what a clock is and how to synchronise one. You do a lot of that.

010511, 10:57 PM #927

010511, 11:03 PM #928
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 3,595
The most obvious mistake you keep repeating is this: you ignore any questions, and just go over the same old ground as if everbody who has read it 900 times already needs to see it again.
I could trawl back over the thread and quote some of the questions you have ignored, or not attemptedthis is the telling part, it's more than a possibility that you simply don't understand them, or you just don't know the answer or if there is an answer.
But that would be a big waste of time, because you'll just ignore them all over again. It was fun, even a bit of a laugh, but now it's more like finding out someone dropped their ciggy butt into your can of beer.

010511, 11:04 PM #929
I'll try to draw something, but in the meantime, here is a verbal explanation. Lay down a tape measure on the "floor" of the absolute rest frame. Now lay another tape measure down at a right angle to the first one. Call the measurements on one of the tape measures "x" and call the measurements on the other tape measure "y". When the train moves, we will use "x" to measure how far the train moves. We will use "y" to measure how far the skate moves, because the skate travels a path that is 90 degrees to the path of the train.
Let's start with the skate located at position (0,0) where the first zero is the "x" value, and the second zero is the "y" value. For this exercise, let's say that only the train moves, and the skate just sits still inside the train. In this case, let's say that the skate moved from (0,0) to (12,0) because of the movement of the train. Notice that the skate has moved a distance of 12. I am just making these numbers up for this simple exercise.
Now let's try things a little differently. This time, let's say that only the skate moves, and the train stays motionless. In this case, let's say that the skate moved from (0,0) to (0,8) because of the movement of the skate. Notice that the skate has moved a distance of 8 for this case. Again, I'm just making these numbers up.
And finally, let's combine both motions together. We will let the skate move at the same time as the train moves. In this case, the skate moves from (0,0) to (12,8) because of the movement of the skate and the train combined. As you can see, the skate has moved in both the "x" and "y" directions. If there had been an elevator on the train, the skate could also have also moved along the "z" direction, but let's keep things simple for now.
Anyway, do you know how to calculate how far the skate moved? If not, here is the answer:
d = sqrt(12^2 + 8^2)
d = sqrt(144 + 64)
d = sqrt(208)
d = 14.422
In case you don't know those symbols, the "sqrt" means square root, and the "^2" means raised to the second power. Raising to the second power is also called squaring, which is just another way of saying that the number is multiplied by itself.
If we want to talk about the "absolute velocity" of the skate, then we must consider that it actually traveled a distance of 14.422, because it went from point (0,0) to point (12,8). The line that connects those points is the vector that represents the direction of the absolute velocity.
Now let's get to some light signals. If the skate has a length of 1, and a beam of light travels the length of the skate, how far does the light travel according to the absolute rest frame? Here is the answer:
d = sqrt(12^2 + 9^2)
d = sqrt(144 + 81)
d = sqrt(225)
d = 15
The reason I used 9 instead of 8 is because I added the length of the skate to the "y" dimension. The vector that represents the direction of the velocity of the light is the line that goes from point (0,0) to (12,9). This is the information that I have been using to show that your calculations are not working with a light speed of "c" in the absolute rest frame. Does this make sense yet?

010511, 11:06 PM #930

010511, 11:08 PM #931
 Posts
 3,595
Well I would, but Oprah is on, so there are more better things to do . . .
Post #912 demolishes Einstein's concept of the relativity of simultaneity.

010511, 11:33 PM #932
I understand what you are telling me. I was measuring the distance the skate traveled inline with the train's motion, not at 90 degrees to the train's motion.
There is two different velocities we are talking about here, one of the train and one of the skate. The two velocities are separate. The train in the direction of the tracks, and the skate in the direction 90 degrees to the tracks. The velocity of each light is in the direction of the object's motion.
So, there is an x velocity and a y velocity. They are separate velocities. You can't combine them and say the skate arrived at (12,9) like it traveled in a straight line from (0,0). There are two separate velocities, one of the x and one of the y.Last edited by Motor Daddy; 010511 at 11:39 PM.

010511, 11:37 PM #933

010511, 11:42 PM #934

010511, 11:46 PM #935

010511, 11:48 PM #936

010511, 11:49 PM #937
Think of a light source in space, like a small sun. Each ray of light travels away from the source in a straight line. There is one distance the light travels. It is impossible for light to leave a source and travel to 12,9. It either travels 12 away, or 9 away, depending on the time.

010511, 11:54 PM #938
You don't think I can shine a laser pointer from (0,0) to point (12,8) in the absolute rest frame? You dont think a sphere of light set off at point (0,0) will eventually cross the point (12,9)?
Wow.
If the train had not moved, and the skate had not moved, the light would have traveled from (0,0) to (0,1). Do you dispute this simple concept?

010511, 11:56 PM #939

010511, 11:58 PM #940
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