Question

1. as you are standing on the sidewalk, a car speeds past you blowing its horn. you notice that as the car passes you and speeds away, the sound gets quieter and lower in pitch. explain what is happening to the sound wave of the car horn as it passes.

Explanation:

This is the Doppler effect. When the car moves away, sound waves are stretched (longer wavelength, lower frequency/pitch). Also, distance increases, so sound intensity (loudness) decreases as energy spreads over a larger area.

Answer:

As the car moves away, the Doppler effect occurs: 1) Sound waves are stretched (wavelength increases, frequency/pitch decreases) because the source (car) moves away from the observer. 2) Loudness decreases because the sound energy spreads over a larger area as distance from the observer increases.