Answer:
The changes in sound waves as a race car approaches and moves away from the crowd can be explained by the Doppler Effect. Here are the models and explanations that accurately describe this phenomenon:
Doppler Effect:
The Doppler Effect describes how the frequency of sound waves changes relative to an observer when there is relative motion between the source of the sound and the observer.
As the race car approaches the crowd, the sound waves are compressed in front of the car, leading to an increase in frequency (higher pitch) perceived by the observers.
As the race car moves away from the crowd, the sound waves are stretched out behind the car, causing a decrease in frequency (lower pitch) heard by the observers.
Explanation:
