Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Beyond the Linear Damping Model for Mechanical Harmonic Oscillators   The steady state motion of a folded pendulum has been studied using
frequencies of drive that are mainly below the natural (resonance) frequency of
the instrument. Although the free-decay of this mechanical oscillator appears
textbook exponential, the steady state behavior of the instrument for
sub-resonance drive can be remarkably complex. Although the response cannot be
explained by linear damping models, the general features can be understood with
the nonlinear, modified Coulomb damping model developed by the author.

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The categories of this paper are: eess
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The categories of this paper are: mtrl-th
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The categories of this paper are: nlin
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The categories of this paper are: comp-gas
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The categories of this paper are: hep-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: acc-phys
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The categories of this paper are: chem-ph