Mechanical resonance displaying changes in phase to large audiences
作者:
R. Dorner,
L. Kowalski,
M. Stein,
期刊:
American Journal of Physics
(AIP Available online 1995)
卷期:
Volume 63,
issue 4
页码: 364-369
ISSN:0002-9505
年代: 1995
DOI:10.1119/1.17921
出版商: American Association of Physics Teachers
关键词: OSCILLATIONS;RESONANCE;EDUCATIONAL TOOLS;AMPLITUDES;FREQUENCY DEPENDENCE;LABORATORY EQUIPMENT;MECHANICAL VIBRATIONS;LASER RADIATION;LIGHT EMITTING DIODES
数据来源: AIP
摘要:
This article describes lecture demonstration apparatus for displaying free and forced oscillations of a mechanical system to a large class. The setup described won first prize at the AAPT apparatus competition in August 1994. A Plexiglas blade clamped at one end is magnetically driven by a low‐frequency generator–amplifier. The frequencies are so low (between 0.2 and 1.2 Hz) that visual observations of displacements are possible. The driving voltage, associated with the force applied, is visualized with a row of 20 light‐emitting diodes, a laser pointer projecting displacements, and a photosensor providing sound cues for phase references. Dependence of amplitude and phase on frequency can be seen, heard, and recorded by a large group of students. The apparatus is simple enough to be replicated and used at all levels of physics teaching. Technical details on the LED display unit, and some theoretical considerations, are described in two appendices.
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