The pumping of a swing from the standing position
作者:
William B. Case,
期刊:
American Journal of Physics
(AIP Available online 1996)
卷期:
Volume 64,
issue 3
页码: 215-220
ISSN:0002-9505
年代: 1996
DOI:10.1119/1.18209
出版商: American Association of Physics Teachers
关键词: CLASSICAL MECHANICS;HARMONIC OSCILLATORS;PENDULUMS;RESONANCE;03.20
数据来源: AIP
摘要:
The pumping of a swing from a standing position is modeled as a rigid object forced to rotate back and forth at the lower ends of supporting ropes. This model after some approximations leads to a harmonic oscillator with driving and parametric terms. It is then argued that in the regime of the common playground swing the driving terms dominate and the pumping of a swing in the standing position is best characterized as a driven oscillator. Examination of the relative phase of the swinger and the swing also supports this conclusion. This model is compared with earlier work which claimed that the swing pumped by a standing swinger is characterized as a parametric oscillator. Simple demonstrations of both mechanisms are described. A comparison of pumping while standing and seated is also made.
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