Introduction to SAT II Physics - FreeExamPapers

A cop car drives at 30 m/s toward the scene of a crime, with its siren blaring at a frequency
of 2000 Hz. At what frequency do people hear the siren as it approaches? At what frequency
do they hear it as it passes? The speed of sound in the air is 343 m/s.
As the car approaches, the sound waves will have shorter wavelengths and higher
frequencies, and as it goes by, the sound waves will have longer wavelengths and lower
frequencies. More precisely, the frequency as the cop car approaches is:
The frequency as the cop car drives by is:
Key Formulas
Frequency
of Periodic
Oscillation
Speed of
Waves on a
String
Wave
Speed
Wavelengt
h for the
Harmonic
Series
Frequency
for the
Harmonic
Series
Beat
Frequency
Doppler
Shift
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