Damped, Driven Oscillations on a Linear Air Track - An Introduction to Resonance for Freshman and Sophomore Students in Experimental Physics

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An experiment will be developed to enable students, especially physics majors, to be better prepared to study resonance processes at the intermediate and advanced levels by providing experience with a simple resonance system as part of an introductory course in experimental physics. The system to be studied is the classical damped, driven harmonic oscillator: a mass and spring system acted upon by an external damping force and a periodic driving force. The equipment required includes a linear air track system, a specially designed loud speaker and a sine wave generator/amplifier. The air track provides a nearly frictionless surface upon which the mass-spring system oscillates. The speaker, driven by the sine wave generator/amplifier, provides a periodic driving force at frequencies in the 0.10-2.00 Hz range. Damping is introduced by attaching ceramic magnets to the sides of the air track glider, producing eddy currents in the track as the glider oscillates. Students will measure the period of free oscillations of the mass-spring system, the damping time constant, and the amplitude of forced oscillations as a function of driving frequency for varying amounts of damping. The experience gained will help students to relate the theoretical treatment of resonance in our physical mechanics course to a number of experiments in the advanced laboratory course, where resonance processes are investigated in depth.