Answer:
The length is 
Explanation:
From the question we are told that
The frequencies of the two successive harmonics are
, 
The speed of sound in the air is 
Generally the frequency of a given harmonic is mathematically represented as

Here n defines the position of the harmonics
Now since the position of both harmonic is not know but we know that they successive then we can represented them mathematically as

and

So

=> 
=> 
Answer:
air resistance, gravitational force
Answer:
I Will say the Answer is A
Explanation:
The Doppler effect occurs when a source of sound or light
moves either toward or away from the observer.