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Sound boom in US Navy Blue Angels shows

(2023-10-28 07:07:01) 下一個

 

Sonic boom is an impulsive noise similar to thunder. It is caused by an object moving at the speed of sound -- about 343 meters per second or 767 miles per hour at sea level and at 68 degrees Fahrenheit.  

When two objects reach the same frequency, a phenomenon in physics called resonance occurs.

Resonance is a phenomenon that occurs when an object or system is subjected to an external force or vibration that matches its natural frequency. When this happens, the object or system absorbs energy from the external force and starts vibrating with a larger amplitude. https://en.wikipedia.org/wiki/Resonance?

Resonance, could happen in your daily life. For example,  you turn your faucet on slowly, gradually turn the faucet handle up, so water flows out with increased speed. At a certain point the flow speed reaches the natural frequency of the copper pipe. We could hear a laud vibration sound of the pipe. Once my landlord was at this scenario, she was scared and wanted to call a plumber, I said "turn your faucet handle either up or down, you will not hear this sound any more". She did and the vibration stopped.

I asked Bard, tuning a radio station, is it a phenomenon of resonance.

Bard answer:

Yes, tuning a radio station is a phenomenon of resonance. Resonance is a phenomenon in which an object or system absorbs or emits more energy at a certain frequency than it does at other frequencies. This is because the object's or system's natural frequency matches the frequency of the incoming energy.

Radio stations broadcast their signals at specific frequencies. When you tune your radio to a particular station, you are adjusting the resonant frequency of the radio's receiver circuit so that it matches the frequency of the radio station's signal. This allows the radio to receive the signal from the radio station and reject signals from other radio stations.

Radio receivers typically use an LC circuit to tune to a specific frequency. An LC circuit is a circuit that consists of an inductor (L) and a capacitor (C). The resonant frequency of an LC circuit is given by the following equation:

f_r = 1 / (2 * pi * sqrt(L * C))

where:

  • f_r is the resonant frequency in hertz (Hz)
  • L is the inductance in henrys (H)
  • C is the capacitance in farads (F)

By adjusting the inductance or capacitance of the LC circuit, the resonant frequency of the circuit can be changed. This is how radio receivers are able to tune to different radio stations.

As another example, a bridge collapsed in 1850, it was also a resonance event:

https://en.wikipedia.org/wiki/Angers_Bridge

 

9 Everyday Examples Of Resonance:

https://studiousguy.com/everyday-examples-of-resonance/

 

In an air show, this could also happen. When the jet reach the speed of the sound, you will heard a boom (the sound boom) and you will also see a cone- shaped cloud if there is enough water vapor in the air. It happened that the days were all cloudy when all my pictures were taken.  

 

On leveled photos (3 continuous shots, 2007):

 

On a chopped, sharpened photo (2008):

On a chopped, sharpend photo (2009):

On youtube (not mine):

 

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