Sound and Music - Mission SM4 Detailed Help

TRUE      or      FALSE:
Ken Fused is standing on a corner when a police car passes by with its siren on. Ken hears a different pitch when the police car is approaching him than when it is past him. This is because the siren on the front of the car is set to a higher pitch than the siren on the back of the car.
 
(Note: The actual true-false statement is randomly selected from a collection of statements and may differ from the one shown above.)


 
Definition of the Doppler Shift:
The Doppler shifti s the alteration of the frequency observed of waves that occurs whenever the wave source is moving towards or away from the observer (or the observer is moving towards or away from the wave source).


 
Poor Ken is really confused. And he probably does not believe in the Doppler shift. The difference in pitch observed by Ken is fully explainable by the Doppler shift. As the police car approaches, the observed frequency of sound waves is higher than the frequency at which sound waves are emitted by the siren. And as the police car moves away from Ken, the observed frequency of sound waves is lower than the frequency at which sound waves are emitted by the siren. This is the Doppler shift.