Question

A 2450-Hz sound source and an observer are moving away from each other. The source is moving at 15.0m/s, and the observer is moving at 25.0m/s. Assuming the speed of sound to be 343 m/s, what is the frequency heard by the observer?

Answer 1

Answer:

$f'=2176.256983Hz$

Explanation:

The relationship between observed frequency f' and the emitted frequency f is given by the doppler effect equation. In this case the observer and the source are moving in opposite direction away from each other, so:

$f'=\frac{c-v_0}{c+v_s} f$

Where:

$c=Speed-of-the-sound-waves=343m/s$

$v_0=Velocity -of-observer=25m/s$

$v_s=Velocity -of-source=15m/s$

$f=Emitted -frequency=2450Hz$

$f'=Observed-frequency$

Evaluating the data in the equation:

$f'=\frac{343-25}{343+15}*2450=2176.256983Hz$