A sound source of frequency 1000 Hz moves at 40.0 m/s toward a listener who is at rest.What is the apparent frequency heard by the listener? (speed of sound = 340 m/s)
A) 853 Hz
B) 872 Hz
C) 1130 Hz
D) 1170 Hz

Question

Quizplus · Accepted Answer

First, we need to determine the speed of the sound wave relative to the listener. This can be found by subtracting the speed of the observer from the speed of sound: 
340 m/s - 0 m/s (since the listener is at rest) = 340 m/s.

Next, we need to determine the frequency that the listener hears. We can use the Doppler effect equation:

f' = f (v + vo) / (v + vs)

Where: 
f = the frequency of the source 
v = the speed of sound 
vo = the velocity of the observer 
vs = the velocity of the source

Plugging in the values, we get:

f' = 1000 Hz (340 m/s + 0 m/s) / (340 m/s - 40.0 m/s) 
f' = 1130 Hz

Therefore, the apparent frequency heard by the listener is 1130 Hz, which is option C.

A Sound Source of Frequency 1000 Hz Moves at 40