- #1
Myslius
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<<Unacceptable Link>>
Why in C's FOR object doesn't fit?
Why in C's FOR object doesn't fit?
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C FOR Loop Paradox: Unraveling the Mystery
- Thread starter Myslius
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In summary, the conversation discusses the barn and ladder paradox and why the ladder appears to not fit inside the barn in certain reference frames. It is determined that the animation used to demonstrate the paradox may not accurately account for Thomas rotation and the direction of compression. The conversation ends with a discussion of how time dilation can affect the orientation of the object in extreme velocities.
- #2
yuiop
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Who is C? What is the object?
I assume you are talking about the barn and ladder paradox. If so I assume you mean the object to be the ladder and in the rest frame of the ladder the ladder does not appear to fit in the barn, because in the frame the barn is length contracted and is measured to be shorter than the ladder. in this reference frame, the ladder does not have to fit, because the doors are not simultaneously closed in this reference frame, so the ladder can stick out one end of the barn or other.
It is only in the reference frame of the barn that the doors are simultaneously closed, but that is not a problem, because in the reference frame, the ladder is length contracted relative to the barn and fits inside the barn with both doors closed.
I assume you are talking about the barn and ladder paradox. If so I assume you mean the object to be the ladder and in the rest frame of the ladder the ladder does not appear to fit in the barn, because in the frame the barn is length contracted and is measured to be shorter than the ladder. in this reference frame, the ladder does not have to fit, because the doors are not simultaneously closed in this reference frame, so the ladder can stick out one end of the barn or other.
It is only in the reference frame of the barn that the doors are simultaneously closed, but that is not a problem, because in the reference frame, the ladder is length contracted relative to the barn and fits inside the barn with both doors closed.
- #3
Myslius
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Have you looked at the link?
- #4
jartsa
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I would guess it's because the person that made the animation did not make the red object lorentz contracted enough.
Even the leading edge does not seem to fit. With the tilting and with the the correct lorentz contraction it should just exactly fit.
Even the leading edge does not seem to fit. With the tilting and with the the correct lorentz contraction it should just exactly fit.
- #5
Myslius
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jartsa, you can make it Lorentz contracted till it becomes a line, still don't fit.
- #6
yuiop
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Did not see the link for some reason. Yes, it looks like red B object if having a problem fitting inside the blue tube A in C's FOR, but I am not sure how accurate the animation is. It looks like there has been an attempt to take account of Thomas rotation when the red square B is moving diagonally. The degree of Thomas rotation depends on the order of the transformations and the error might be there.Myslius said:
In C's FOR, the red object should be length contracted in the vertical direction to the same extent as the inside of the blue tube and also length contracted in the horizontal direction to the same extend as in A's FOR, so it appears the animation is not accurate.
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- #7
jartsa
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Myslius said:
Depends on the direction of the compression. Oh yes I see that if the direction of the compression is the same as the direction of the motion in the animation, then the line would not fit.
But the direction of the motion changes, when the the extra compression is caused by extra vertical speed. Motion becomes more vertical.
- #8
Myslius
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"Length contraction is only in the direction parallel to the direction in which the observed body is traveling".
And so we have a problem... It doesn't care about vertical or horizontal contraction. If it were to compress in x and y direction equally, it's just stating that the object becomes smaller, but not length contracted.
That's not relativistic length contraction description.
And so we have a problem... It doesn't care about vertical or horizontal contraction. If it were to compress in x and y direction equally, it's just stating that the object becomes smaller, but not length contracted.
That's not relativistic length contraction description.
- #9
yuiop
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This sketch shows how the red object actually would be skewed.
The general rule is that when an object is moving orthogonally to the intended boot direction, edges that are initially parallel to the intended boost direction will be rotated after the boost, while edges of the object that are orthogonal to the intended boost direction will not rotate.
The general rule is that when an object is moving orthogonally to the intended boot direction, edges that are initially parallel to the intended boost direction will be rotated after the boost, while edges of the object that are orthogonal to the intended boost direction will not rotate.
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- #10
Myslius
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yuiop, yes, now it fits (when A moves vertically relative in C's coordinate system). Let's say A comes from the right to the left, doesn't fit.
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- #11
jartsa
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I see, horizontal edges stay horizontal, ok, thank you yuiop.No downwards motion of red rectangle - the side edges are vertical
Some downwards motion of red rectangle - the side edges are tilted
Huge amounts of downwards motion of red rectangle - the side edges are almost vertical again
At enormous vertical velocities time dialtion causes the sideways motion almost to stop, then there's no reason for the rectangle to be tilted.
Some downwards motion of red rectangle - the side edges are tilted
Huge amounts of downwards motion of red rectangle - the side edges are almost vertical again
At enormous vertical velocities time dialtion causes the sideways motion almost to stop, then there's no reason for the rectangle to be tilted.
- #12
Dale
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The link in the OP is not acceptable to PF standards, so the thread must be closed.
1. What is a C for loop?
A C for loop is a control structure in the C programming language that allows a section of code to be repeated a specified number of times. It consists of three parts: initialization, condition, and increment/decrement.
2. What is the paradox associated with C for loops?
The paradox associated with C for loops is that the loop will continue to run even after the condition is no longer true. This is because the increment/decrement part of the loop is executed after each iteration, potentially changing the value of the condition.
3. How can the C for loop paradox be avoided?
The C for loop paradox can be avoided by carefully designing the condition and increment/decrement parts of the loop. It is important to ensure that the loop will eventually terminate by making the condition dependent on a variable that is modified within the loop.
4. What are some common errors associated with C for loops?
Some common errors associated with C for loops include infinite loops, where the loop condition is never met and the loop runs indefinitely, and off-by-one errors, where the loop either runs one too many or one too few times due to incorrect initialization or increment/decrement.
5. How important is it to understand C for loops in computer science?
C for loops are a fundamental concept in computer science and are used in many programming languages. Understanding how they work is essential for writing efficient and error-free code. It is also important for understanding more complex control structures and algorithms.
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