# physics

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Thread starter 6 months ago
#1
The Doppler effect, which occurs both in sound and electromagnetic waves—including light waves—has a number of applications. Astronomers use it, for instance, to gauge the movement of stars relative to Earth. Doppler radar provides information concerning weather patterns, but some people experience it in a less pleasant way: when a police officer uses it to measure their driving speed before writing a ticket.
 Drawing upon the discussion in class about Doppler Effect, relate your knowledge to support the daily experience of the observation when a police siren is observed to change pitch as it passes a stationary observer, e.g. you.
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6 months ago
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Thread starter 6 months ago
#3
(Original post by ThiagoBrigido)
What is this?
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6 months ago
#4
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6 months ago
#5
(Original post by Mokhions)
The Doppler effect, which occurs both in sound and electromagnetic waves—including light waves—has a number of applications. Astronomers use it, for instance, to gauge the movement of stars relative to Earth. Doppler radar provides information concerning weather patterns, but some people experience it in a less pleasant way: when a police officer uses it to measure their driving speed before writing a ticket.
 Drawing upon the discussion in class about Doppler Effect, relate your knowledge to support the daily experience of the observation when a police siren is observed to change pitch as it passes a stationary observer, e.g. you.
I have limited knowledge on this but I hope I can help.

Stars are said to be 'red- shifted' when their distance from Earth increases, which also, in turn, increase their velocity. Applying this to your scenario, the stationary object, which is you, epitomises the Earth. So when the police car's distance is closer to you, the distance between the wavelengths are closer together as well which makes the pitch higher. As the car moves away from you, the wavelengths stretch which make the pitch lower.
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