Editing Ladder paradox (section)

==Man falling into grate variation==
[[File:ladder paradox grate variation.svg|thumb|300px|A man (represented by a segmented rod) falling into a grate]]

This early version  of the [[physical paradox|paradox]] was originally proposed and solved by [[Wolfgang Rindler]]<ref name="lengthcontraction">{{Cite journal|author=Rindler, Wolfgang|title=Length Contraction Paradox|journal=American Journal of Physics|year=1961|volume=29|issue=6|pages=365–366|doi=10.1119/1.1937789|bibcode = 1961AmJPh..29..365R }}</ref> and involved a fast walking man, represented by a rod, falling into a grate.<ref>{{cite book|author1=Edwin F. Taylor |author2=John Archibald Wheeler |title=Spacetime Physics: Introduction to Special Relativity|url=https://archive.org/details/spacetimephysics00edwi_0 |url-access=registration |year=1992|publisher=W. H. Freeman|location=New York|isbn=0-7167-2327-1|pages=[https://archive.org/details/spacetimephysics00edwi_0/page/116 116]}}</ref> It is assumed that the rod is entirely over the grate in the grate frame of reference before the downward acceleration begins simultaneously and equally applied to each point in the rod.

From the perspective of the grate, the rod undergoes a length contraction and fits into the grate.  However, from the perspective of the rod, it is the ''grate'' undergoing a length contraction, through which it seems the rod is then too long to fall.

The downward acceleration of the rod, which is simultaneous in the grate's frame of reference, is not simultaneous in the rod's frame of reference. In the rod's frame of reference, the front of the rod is first accelerated downward (shown in cell 3 of the drawing), and as time goes by, more and more of the rod is subjected to the downward acceleration, until finally the back of the rod is accelerated downward. This results in a bending of the rod in the rod's frame of reference. Since this bending occurs in the rod's rest frame, it is a true physical distortion of the rod which will cause stresses to occur in the rod.

For this non-rigid behaviour of the rod to become apparent, both the rod itself and the grate must be of such a scale that the traversal time is measurable.

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