iii. A sound source and a listener are both at rest on the earth, but a strong wind is blowing front the source toward the listener. Is there a Doppler effect? Why or why not?
Yes, there would still be a Doppler effect in this scenario, despite the sound source and listener being at rest on the Earth.
The Doppler effect is the change in frequency or wavelength of a wave as observed by an observer moving relative to the source of the wave. It occurs due to the relative motion between the source and the observer.
In this case, although the source and the listener are at rest on the Earth, the presence of a strong wind blowing from the source towards the listener introduces relative motion between the two.
The wind causes the air particles in its path to move towards the listener. Since sound waves propagate through the movement of air particles, the wind will compress the air particles ahead of the source and create a "sound wavefront" that moves faster towards the listener than the speed of sound would be without the wind.
As a result, the listener experiences an increased frequency of the sound, causing a higher pitch or tone. This is referred to as the "positive Doppler effect" because the frequency observed by the listener is higher than the actual frequency emitted by the source.
To calculate the magnitude of the Doppler effect in this scenario, you would need to know the speed of the wind, the speed of sound, and the frequency of the sound emitted by the source. Using the formula for the Doppler effect, you can calculate the observed frequency or wavelength.