Question

juan is standing on the street. an ambulance moves toward him and then passes by. what best describes the pitch that juan hears? the pitch remains constant as the ambulance moves toward and then away from juan. the pitch increases and decreases in a repeated pattern as the ambulance passes juan. the pitch drops to a lower pitch once the ambulance passes by juan. the pitch increases to a higher pitch once the ambulance passes by juan.

Explanation:

This is related to the Doppler effect. When the ambulance is moving toward Juan, the sound waves are compressed, resulting in a higher - pitched sound. Once the ambulance passes Juan and moves away, the sound waves are stretched out (longer wavelength), which corresponds to a lower - pitched sound. The first option is incorrect because the pitch changes. The second option is wrong as there is no repeated pattern of increase and decrease; it is a one - time change from high to low. The fourth option is incorrect because the pitch decreases when the ambulance moves away.

Answer:

C. The pitch drops to a lower pitch once the ambulance passes by Juan.