Answer:
The sound of the horn will sound louder as the car approaches.
Step-by-step explanation:
The name “Doppler Effect” is a reference to Austrian physicist Christian Johann Doppler, who studied and described it. This scientist wrote an article in which he states that the frequency of sound perceived by an observer depends on the relative movement between the emitting source of sound and the observer.
A typical example of the Doppler effect is a car horn when approaching or moving away from an observer. As she approaches the observer, the sound is louder; and when the car pulls away, the sound is louder. This is a characteristic phenomenon of any wave propagation, and it is much more present in everyday life than we think.