A source emits sound with a frequency of 18,002 Hz. Both it and an observer are moving toward each other, each with a speed of 130 m/s. What frequency (in Hz) does the observer hear

The frequency heard by the observer is 24,830.35 Hz.

Explanation:

Given;

frequency of the source, Fs = 18,002 Hz

speed of the source, Vs = 130

speed of sound in air, V = 343 m/s

Apply Doppler effect, as the source and the observer move closer to each other, the frequency heard by the observer increases because of decrease in distance.

where;

f₀ is the frequency heard by the observer

Therefore, the frequency heard by the observer is 24,830.35 Hz.