What is the frequency does a stationary observer hear when a train approaches her with a speed of 30 m/s.The frequency of the train horn is 0.600 kHz and the speed of sound is 340 m/s.
A)551 Hz
B)600 Hz
C)653 Hz
D)658 Hz

Question

Quizplus · Accepted Answer

The frequency heard by a stationary observer when a source approaches is given by the formula $f' = \frac{f}{1 - \frac{v}{v_s}}$, where $f'$ is the observed frequency, $f$ is the source frequency, $v$ is the speed of the source, and $v_s$ is the speed of sound. Plugging in the given values: $f' = \frac{0.600 \times 10^3}{1 - \frac{30}{340}} = 658$ Hz.

What Is the Frequency Does a Stationary Observer Hear When