The Doppler effect in acoustics

Calculator said sound frequency and wavelength.

The so-called Doppler effect, we often see on the streets, when the road going car with a siren (eg ambulance). And the closer approaching us such a machine, the more we hear the sound of a siren, and when the car is right next to us, we clearly hear the sound, we no longer interfere with the distance and the sound is not jammed or anything.

The Doppler effect in acoustics can be described as follows:

First, to change the frequency of view:

Then I think to change the wavelength of the sound itself

When approaching the source velocity v 'put-minus, and if on the contrary - is removed, then we take a plus.

V - speed of sound (since this value to the air, it is customary to select a temperature 20oC).

Effect Doppler in acoustics
 hourThoth signal, Hz:
 Observed hourThoth, Hz:
 Length wave signal, m:
 Observed length wave, m: