Answer:
Correct answer: 8. The wave on the left screen has a higher frequency
9. The wave on the right screen represents sound of the siren after it has passed you.
Step-by-step explanation:
8. The formula for the frequency is
f = 1/T where T is period
on the left screen the period T is smaller so the frequency is higher
9. In accordance with the Doppler effect, the frequency decreases when the siren is moving away from the sound receiver
God is with you!!!