Question

What causes the increase in pitch as an ambulance siren moves toward you?

A. the sound waves spread farther apart
B. the speed of sound waves changes
C. the amplitude of the sound waves changes
D. the sound waves become compressed

Answer 1

I think D, since the observed frequency is increased

Answer 2

ooh okay, makes sense :) thank you!!

Answer 3

with respect to the emitted frequency

Answer 4

:)

Answer 5

ahh okie:)