Doppler Effect: How Does the Ambulance Siren Vary?

[xxChrisxx]

http://www.school-for-champions.com/science/sound_doppler_equations.htm

Read 'Source Moving at an Angle' section.

 

[Doc Al]

Turv, you're wrong mate. If a constant speed (anything) heads DIRECTLY towards you you won't hear a pitch change. If it comes PAST to you, you will.

You are correct, of course. Part of the problem here is sloppy language. When something comes directly toward you at constant speed, you will hear an unchanging, constant pitch which will be higher than the pitch of the source (and as given by the usual Doppler equations). If it goes past you, then you'll hear a changing pitch.

Chris,

I have just had a warning off a mentor which is totally unjustified, the doppler equation will work with constant velocity are you saying everything needs to accelerate to get the doppler effect, this would just be nonsense, if the mentors want (yes men) then why not ban everyone and have morons posting saying yes mentor 3 bags full mentor, yes your right mentor ( When they can't even post the equation in there defence) i posted the authentic doppler equation, is he wrong? YES MENTOR!

Haven't you embarrassed yourself enough?

 

[DrGreg]

ok, seeing as this came up on the f1 thread and was then rightly deleted.

Turv, you're wrong mate. If a constant speed (anything) heads DIRECTLY towards you you won't hear a pitch change. If it comes PAST to you, you will.

Even the shoddyness that is wiki has this on it.

Chris,

I have just had a warning off a mentor which is totally unjustified, the doppler equation will work with constant velocity are you saying everything needs to accelerate to get the doppler effect, this would just be nonsense, if the mentors want (yes men) then why not ban everyone and have morons posting saying yes mentor 3 bags full mentor, yes your right mentor ( When they can't even post the equation in there defence) i posted the authentic doppler equation, is he wrong? YES MENTOR!

Hold on! Don't get too excited!

When we talk of change, change relative to what?

When a car heads straight towards you, its frequency will have changed relative to what it would have been if it was stationary. But if you've never heard it stationary, you won't know that, you'll just hear a constant higher pitch. (If you did hear it when it was stationary, then you'd hear the pitch increase as it accelerated.) Then the car will hit you and you won't hear anything at all, because you'll be dead.