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**1. Homework Statement**

:

An ambulance has a siren of frequency 880 Hz. You are sitting at a stop light as the ambulance passes you, traveling at a constant 22 m/s. If the speed of sound is 343 m/s, what is the change in the frequency that you hear as the ambulance passes you?

A

-53 Hz

B

-60 Hz

C

-56 Hz

D

-113 Hz

E

-116 Hz

**2. Homework Equations**

WHERE FL and vL are the frequency and velocity of sound heard by the personL

fs and vs are the frequency and velocity of sound emmited by the source

**3. The Attempt at a Solution**

using the equation we get FL=880x(343+0)/(343-22) therefore FL=940.3Hz

the difference is FL-Fs=940.3-880=60.311Hz

but its not correct.

the correct answer is -113Hz why???