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

在实验物理入门课程中，我们将提供一个简单共振系统的经验，使学生，特别是物理专业的学生，能够更好地为中高级共振过程的研究做准备。要研究的系统是经典的阻尼驱动谐振子：一个由外部阻尼力和周期性驱动力作用的质量和弹簧系统。所需的设备包括一个线性空气轨道系统，一个专门设计的扬声器和一个正弦波发生器/放大器。空气轨道提供了一个几乎无摩擦的表面，质量-弹簧系统在其上振荡。扬声器由正弦波发生器/放大器驱动，在0.10-2.00 Hz范围内提供周期性驱动力。阻尼是通过将陶瓷磁铁附着在空气轨道滑翔机的两侧来引入的，当滑翔机振荡时，在轨道上产生涡流。学生将测量质量-弹簧系统的自由振荡周期，阻尼时间常数，以及作为不同阻尼量驱动频率函数的强迫振荡幅度。所获得的经验将帮助学生将物理力学课程中共振的理论处理与高级实验课程中的一些实验联系起来，在这些实验课程中，共振过程将被深入研究。

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.