Tacoma Narrows Bridge Collapse "Gallopin' Gertie"
Why Physics Stack Exchange recommends it
Physics Stack Exchange answerers and commenters link it as the classic visual example when explaining resonance and aeroelastic flutter.
Recommended by 0 people across 0 different months, 2013 to 2019.
What it is
A short clip of the 1940 Tacoma Narrows Bridge twisting and collapsing in a windstorm, uploaded by Tony C with a brief written history of the bridge. It is the well-known archival footage of "Galloping Gertie" and runs under six minutes.
What people said
Cites daaxix · 2013-01 · Physics Stack Exchange · on “What is actually a resonating vibration and resonance?”
[this video] is a video about the Tacoma Narrows Bridge failure, due to aeroelastic flutter at or near the bridges natural resonant frequency...
Cites docscience · 2016-11 · Physics Stack Exchange · on “Non-resonant but efficient frequencies”
The details they don't put in physics textbooks, but that you likely learn from engineering experience is that resonance depends not only on internal structure of the system but how energy flows in and out. A resonant system tends to trap energy and that energy may or may not necessarily be admissible at the resonant frequency of the system. It depends on the internal structure. Although the more common means of energy transfer for a swing is a cycle by cycle push in one direction, it's also possible to have a person in front also deliver a push such that the rate of energy input to the system is doubled. Each input, the same amplitude but 180 degrees out of phase with one another. You show
Cites docscience · 2016-12 · Physics Stack Exchange · on “Resonance- sound”
Resonance is a property that some systems exhibit due to their specific structure, but fundamentally involves the trapping and a structural means by which energy can flow within the system between different states of energy . The trapping of energy means that the system structure enables the system to admit at least as much energy as what energy is lost by the system. And the flow between internal states means that energy at some times may exist as potential energy and at other times as kinetic energy, or in other types of systems as electrical and magnetic fields. Resonant systems are defined as having modes or natural frequencies and these are states of internal energy flow at which there
Cites David White · 2019-04 · Physics Stack Exchange · on “What is the reason behind resonance?”
In my opinion, your instructor has no in-depth understanding of resonance, as he mentioned in his statement about merely memorizing a statement from the author that he was using. Kinetic energy increases quadratically and potential energy increases linearly, but both energy forms increase monotonically, meaning that there is nothing cyclic about them. For resonance to occur, you need to interact with a cyclic process, which is usually modeled with a sine function. In your interaction with the cyclic process, your addition of energy to the process needs to be in phase with that process, such that each time you interact with it, you increase the amplitude of the sine wave that describes it. Fo