Question

Why did the boy hear the pitch of the sound change? What does this tell us about the frequency sound? Support your conclusion based on results from from the experiment and your knowledge of sound waves

Answer 1

Due to the Doppler effect

Step-by-step explanation:

This effect is called "Doppler effect".

It occurs when there is a source of a wave in relative motion with respect to an observer.

In this situation, there is a change in the apparent frequency of the sound, as observed by the observer. In particular, the apparent frequency is given by:

`f'=(v\pm v_o)/(v\pm v_s)f`

where

f is the real frequency of the wave

f' is the apparent frequency

v is the speed of the wave

`v_o` is the velocity of the observer

`v_s` is the velocity of the wave source

This phenomenon occurs, for instance, with sound waves; a daily example is when we hear the sound of the siren of an ambulance. We have 2 possible situations:

- When the ambulance is moving towards us, we hear an increase in the frequency of the sound

- When the ambulance is moving away from us, we hear a decrease in the frequency of the sound