Jacobi elliptic functions are flexible functions that appear in a variety of
problems in physics and engineering. We introduce and describe important
features of these functions and present a physical example from classical
mechanics where they appear: a bead on a spinning hoop. We determine the
complete analytical solution for the motion of a bead on the driven hoop for
arbitrary initial conditions and parameter values.Comment: Accepted for publication in American Journal of Physics. 9 pages, 6
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