Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Dynamics of Relativistic Length Contraction and the Ehrenfest
  Paradox   Relativistic kinematics is usually considered only as a manifestation of
pseudo-Euclidean (Lorentzian) geometry of space-time. However, as it is
explicitly stated in General Relativity, the geometry itself depends on
dynamics, specifically, on the energy-momentum tensor. We discuss a few
examples, which illustrate the dynamical aspect of the length-contraction
effect within the framework of Special Relativity. We show some pitfalls
associated with direct application of the length contraction formula in cases
when an extended object is accelerated. Our analysis reveals intimate
connections between length contraction and the dynamics of internal forces
within the accelerated system.
  The developed approach is used to analyze the correlation between two
congruent disks - one stationary and one rotating (the Ehrenfest paradox).
Specifically, we consider the transition of a disk from the state of rest to a
spinning state under the applied forces. It reveals the underlying physical
mechanism in the corresponding transition from Euclidean geometry of stationary
disk to Lobachevsky's (hyperbolic) geometry of the spinning disk in the process
of its rotational boost. A conclusion is made that the rest mass of a spinning
disk or ring of a fixed radius must contain an additional term representing the
potential energy of non-Euclidean circumferential deformation of its material.
Possible experimentally observable manifestations of Lobachevsky's geometry of
rotating systems are discussed.

31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
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The categories of this paper are: supr-con
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The categories of this paper are: dg-ga
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The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
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The categories of this paper are: nucl-ex