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Wilberforce Pendulum

PIRA DCS: 3A-70.10


Demonstration of coupled oscillations. A Wilberforce pendulum consists of a plumb bob which hangs from a spring. The Wilberforce pendulum has four modes of oscillation: translational (vertical), torsional, and two pendula modes. The bob's moment of inertia can be tuned to demonstrate energy transfer between the translational and torsional modes. The moment of inertia should be adjusted so that the rotational period is approximately equal to the translational period. When the resulting beat frequency is is much smaller than the frequency of the two normal modes energy exchange between the two degrees of freedom is easily observed.


Component List


  • R.M. Sutton, Demonstration Experiments in Physics, S-18, p135.
  • Freier & Anderson,Demonstration Handbook for Physics, Mx-11, page M-61.
  • Ulrich Köpf, Am. J. Phys. 58(9), 833-837 (1990).
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    Wilberforce Pendulum