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warfreak131
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Homework Statement
During a hurricane, a 1,200 Hz warning siren
on the town hall sounds. The wind is blowing
at 55 m/s in a direction from the siren toward
a person 1 km away. With what frequency does
the sound wave reach the person? (The speed of
sound in air is 330 m/s.)
(A) 1,000 Hz
(B) 1,030 Hz
(C) 1,200 Hz
(D) 1,400 Hz
(E) 1,440 Hz
Homework Equations
[tex]f = \left( \frac{c + v_r}{c + v_{s}} \right) f_0 \,[/tex]
C is the velocity of waves in the medium;
Vr is the velocity of the receiver relative to the medium; positive if the receiver is moving towards the source;
Vs is the velocity of the source relative to the medium; positive if the source is moving away from the receiver.
The Attempt at a Solution
Stop me at any point if I'm wrong:
C would be 330 m/s. Vr would be 55, and Vs would be 0?
I try plugging this into the formula, and I always ~1030 Hz, but the answer key (this is from a practice GRE) says that the answer is 1200 Hz. How do they get this answer?