Posted by jean on Friday, April 1, 2011 at 9:10am.
A car traveling at 24.3 m/s honks its horn as it directly approaches the side of a large building. The horn produces a long sustained note of frequency f0 = 213 Hz. The sound is reflected off the building back to the car's driver. The sound wave from the original note and that reflected off the building combine to create a beat frequency. What is the beat frequency that the driver hears (which tells him that he had better hit the brakes!)? Assume the speed of sound in air is 342 m/s.

physics  drwls, Friday, April 1, 2011 at 9:24am
Calculate the Dopplershifted frequency of the received echo, fr.
Let V be the car speed and a the speed of sound.
fr = fo*[(V+a)/(Va)] = 1.153*fo = 246 Hz
Subtract fo from that for the beat frequency, 33 Hz
Answer This Question
Related Questions
 physics  A car traveling at 22.1 m/s honks its horn as it directly approaches ...
 physics  A car traveling at 22.1 m/s honks its horn as it directly approaches ...
 physics  1)As a sound source moves away from a stationary observer, the number ...
 physics  1)As a sound source moves away from a stationary observer, the number ...
 Physics  A man driving a car toward a large vertical wal sounds his horn. The ...
 Physics  A car travelling at 90 km/hr sounds it horn as it approaches a ...
 Physics!!  A car moving at 16.0 m/s, passes an observer while its horn is ...
 physics  1)As a sound source moves away from a stationary observer, the number ...
 DrBob222  A car moving at 16.0 m/s, passes an observer while its horn is ...
 chemistry physics  A car is traveling toward you at 40.0 mi/h. The car horn ...
More Related Questions