- #1

Any Help

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## Homework Statement

A source emits sound with a frequency of 860 Hz. It is moving at 20.0 m/s toward a stationary reflecting wall. If the speed of sound is 343 m/s, what frequency does an observer riding with the source hear?

A

860 Hz

B

913 Hz

C

910 Hz

D

765 Hz-

E

967 Hz

## 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

## The Attempt at a Solution

:[/B]v=343 m/sec

vs=20 m/sec

vL=-vs=-20 m/sec since if it is moving away from the source

fs=860Hz

then using the aboove equation

FL=860Hz=Fs

but it is incorrect? Why?