Question:
I have this medical helicopter that flys by my house every once and awhile. You can hear the chopper when he's miles away, and eventually when he passes. However, as soon as he flys over, you hear the exhaust and then nothing. No deep, rotor sounds. Why is that?
Answers:
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because they're getting closer.Flight-duration differences between flights and return flights?
Because the sound waves created by the main rotter blades are projected forward.Does anyone know the distance planes used to fly between England and Labrador?
This is due to the sound waves being compressed into a more frequent pattern and lessens as the chopper goes by. The same is true for a speeding car, train, any moving object. This is due to the Doppler Effect.How many people fly in the united states per year ?
This is called the Doppler effect. As the helicopter is approaching it compresses the sound waves making it louder. As it passes you hear the effect of the decompressed sound waves. A good example of the is a car going by you on a highway. You would notice it sounds different when its coming towards you as opposed to traveling away from you.More Questions & Answers ...
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