Doppler Effect Wind: Frequency, Velocity, Wavelength

In summary, the frequency of sound remains the same when an observer and source are at rest and a wind blows along the line joining them. The speed of sound also remains the same as it is not affected by wind, but the wavelength increases proportionally to compensate for the increase in speed. This can be added vectorially to the wind velocity.
  • #1
sachin123
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Homework Statement



An observer is in rest.A source of sound is in rest.A wind blows along the line joining the observer and the source.What all remain same in these:
a.frequency b.velocity of sound c.wavelength

Homework Equations



f prime=f(v+w-vo)/(v+w-vs)
Doppler effect

The Attempt at a Solution


frequency has to remain same since there is no relative motion.
v should remain same because wind cannot influence speed of sound.
wavelength has to obviously remain the same (from the above).
But my book says only frequency remains same.
Please explain.
 
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  • #2
The confusion is over the meaning of "speed of sound" here.
The question means as measured relative to the ground, rather than speed in still air.
In this case the speed increases by an amount equal to the wind speed, and the wavelength is made proportionally larger.
f=speed / wavelength
both speed and wavelength increase. (Such that f stays the same.)
 
  • #3
You:In this case the speed increases by an amount equal to the wind speed.


So speed of sound with respect to the ground is 400 m/s when wind velocity is 70 m/s?
Can we add velocity of sound and wind vectorially?
 
  • #4
sachin123 said:
You:In this case the speed increases by an amount equal to the wind speed.


So speed of sound with respect to the ground is 400 m/s when wind velocity is 70 m/s?
Can we add velocity of sound and wind vectorially?

Yes if the speed was 330m/s in still air and we measure the speed in the same direction as the wind blows.
Yes, the velocities are added vectorially.
 

Related to Doppler Effect Wind: Frequency, Velocity, Wavelength

1. What is the Doppler Effect?

The Doppler Effect is the change in frequency or wavelength of a wave as it moves relative to an observer. This effect is commonly observed in sound waves, light waves, and even water waves.

2. How does the Doppler Effect affect wind?

The Doppler Effect can affect wind by changing the frequency, velocity, and wavelength of the wind as it moves relative to an observer. This can impact the perceived speed and direction of the wind.

3. How does the frequency of wind change due to the Doppler Effect?

The frequency of wind can increase or decrease depending on the direction of the wind relative to the observer. If the wind is moving towards the observer, the frequency will increase, and if it is moving away, the frequency will decrease.

4. Can the Doppler Effect be used to measure wind velocity?

Yes, the Doppler Effect can be used to measure wind velocity by analyzing the change in frequency of the wind as it moves relative to an observer. This is commonly used in weather forecasting and radar technology.

5. Is the Doppler Effect the same for all types of waves?

No, the Doppler Effect can vary depending on the type of wave and the medium it is traveling through. For example, the Doppler Effect for sound waves is different from the Doppler Effect for light waves.

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