Question

Unless specifically stated otherwise, you may assume the speed of sound for all the scenarios below is 350 m/s.3.A bird watcher is recording bird songs (making him more of a bird listener than a bird watcher). He records the song of a south African swallow at 560 Hz as it was travelling at 12 m/s towards him. What is the actual frequency of a south African swallow’s song?

Answer 1

Given

The observed frequency is f'=560 Hz

The speed of the source, v'=12 m/s

Speed of sound, v=350 m/s

To find

The actual frequency

Explanation

When the source is moving towards the observer

$\begin{gathered} f^{\prime}=f^(\frac{v}{v-v^{\prime}}) \\ \Rightarrow560=f(\frac{350}{350-12}) \\ \Rightarrow f=540.8\text{ Hz} \end{gathered}$

Conclusion

The actual frequency is 540.8 Hz