Dynamics: Resonance

Example 5: Vibration of a hanging light

The video shows significant movement of a hanging light in a building. The building vibrated due to ground born vibration induced by vehicles nearby while the natural frequency of the hanging light, similar to a pendulum, coincided with a lateral natural frequency of the building. This generated significant movement of the hanging light even though the vibration of the building was very small and unnoticeable.

On the other hand, the hanging light acted as a pendulum tuned-mass-damper and its significant movement reduced insignificantly the lateral vibration of the building. A demonstration of such a phenomenon can be seen in the fourth model demonstration in Vibration Reduction.

(Courtesy of Prof. B Zhuang, Zhejiang University, China)
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