Posted by **Anonymous** on Monday, April 9, 2012 at 10:37pm.

.Two automobiles are equipped with the same single-frequency horn. When one is at rest and the other is moving toward an observer at 14 m/s, a beat frequency of 5.1 Hz is heard. What is the frequency the horns emit? Assume T = 20°C.

- physics -
**drwls**, Tuesday, April 10, 2012 at 6:46am
The frequency difference is 5.1 Hz

(1 + V/a)*f - f = (V/a)*f = 5.1

a is the sound speed (340 m/s), and

V = 14 m/s

Solve for f.

f = 124 Hz

I did not use the exact formula for a doppler-shifted moving source, but this should be close enough.

## Answer This Question

## Related Questions

- Physics - Two cars have identical horns, each emitting a frequency of f= 395 hz...
- physics - Two identical sources S1 and S2 are moving towards an observer P. The ...
- physics - 1)As a sound source moves away from a stationary observer, the number ...
- physics - a car sounds its horn as it travels at a steady speed of 15m/s along a...
- physics - 1)As a sound source moves away from a stationary observer, the number ...
- physics - An observer rides with a moving sound source directly toward a large ...
- physics - Two trains are moving in opposite diections on parallel tracks and are...
- Physics - A train is moving at a speed of 30 m/s toward a stationary observer at...
- Physics - Two ships in a heavy fog are blowing their horns, both of which ...
- Physics - Ultrasound reflected from an oncoming bloodstream that is moving at 30...

More Related Questions