Khan Academy
Let’s derive the formula for how the perceived frequency of a sound changes when its source is moving toward you. Created by Sal Khan.
Watch the next lesson: https://www.khanacademy.org/science/physics/mechanical-waves-and-sound/doppler-effect/v/doppler-effect-formula-when-source-is-moving-away?utm_source=YT&utm_medium=Desc&utm_campaign=physics
Missed the previous lesson? https://www.khanacademy.org/science/physics/mechanical-waves-and-sound/doppler-effect/v/introduction-to-the-doppler-effect?utm_source=YT&utm_medium=Desc&utm_campaign=physics
Physics on Khan Academy: Physics is the study of the basic principles that govern the physical world around us. We’ll start by looking at motion itself. Then, we’ll learn about forces, momentum, energy, and other concepts in lots of different physical situations. To get the most out of physics, you’ll need a solid understanding of algebra and a basic understanding of trigonometry.
About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We’ve also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.
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Source
S teir explanation
thank you very much. you told very understandable
Thank you so much.. you cleared my confusions and doubts…
muchas gracias Sr. Sal.
Esta es la conferencia más detallada e inclusiva a la que he asistido sobre este tema …
Thanks a lot!
Is education everything?
thank u for solving my problem!!!!!!!
mmmmmminus
😡
best video on this so far
I know he made this organization, but Sal is my least favorite person in these videos
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Helped me get through mechanical waves, not just this video obviously! Thanks a lot!
A light source is moving but the light is stationary. It's stationary because every wave generated radiates from the point in space where the light source is or was when the wave was generated. That wave widens thru space and it's center point is fixed. What is it fixed to? It's fixed to that universal coordinate system that is not supposed to exist. If this were not the case, Doppler shifting would not occur.
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Hey KA! I was using your iOS app to watch Doppler Effect videos, and I noticed that this video is missing from the playlist. It provides a bit of a logical gap, so it'd be helpful to update the app (and maybe even the website if it's missing from there too).
i'm pretty sure that someone who's watching a video on Doppler's effect would have reached a level that they know that distance is velocity times time. thank you for still explaining every little thing.
khan academy > physics book
physics books should just be burnt because they are no longer very helpful
thank you so much
who else has an agar.io tab open?!
Brilliant. Thanks so much!
Perfect! Thanks a million
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Thumbs up!!
Argh relying on Khan academy will make me fail my calculus physics class. Can't he do more difficult problems…
Salute Sir !!
It's the same principle. Whether a car is moving towards you at 5 mph or you are moving towards the car at 5 mph is irrelevant, the waves act the same. So, if there is a problem where you are moving towards a stationary object at 5 mph, you can treat it as if the object is moving towards you at 5 mph as well. Or, (even though in relativity this isn't exactly the case) if you are moving towards something at 5 mph and it is moving towards you at 20 mph, you can treat it as if it's moving 25 mph
thank you, this is really helpful. however, i also need an explanation and a formula for the situation where the observer is moving towards the source. do you have a video on this as well?
A distance galaxy is moving away from us at a speed of 32,433,990 m/s. For hydrogen gas in this galaxy, calculate the wavelength (in nm) of the hydrogen alpha line as observed here on earth. Note: The wavelength emitted by hydrogen is measured in the first year physics lab (Expt. 24) to be 656.2 n
Sorry. The relative frequency will decrease :p
@theonlymoak,
In that case it will depend on whether the police and the car being chased are in motion or not. If the car being chased moves faster than the police, then we should take the case where the source is stationary and the observer is moving, in that case, the relative frequency of the pulse emitted will increase. With this, the police will be able to find the relative position of the thief(chased car) by finding the distance.
so i have a question, hopefully someone can answer it. when police use radar guns they are applying the doppler effect. so when the wave hits the car what exactly happens to it? does it now take on the velocity of the car? without changing the velocity of the wave?
great video.
what software are you using to make it?
You saved me from my Physics Periodic Test. TNX m/
wow much better explanation than my teacher did
thanks a lot
Thank you so much 😀 this makes no sense in my textbook haha , but now I get it
Great video!