<span>It all starts from a radio with a loudspeaker . It produces and converts electrical energy and make this a formed of kinetic energy coming out of the speaker. Then, when this kinetic energy is moving and transferred to surroundings or air, it will let people feel the motion being created by the air. Finally, it reaches the people and hears this as sound.
This is an example on how we trace the transformation of on signal from radio and how it reaches to people as sound or as a music.</span>
Answer:
The value is 
Explanation:
From the question we are told that
The frequency of each sound is
The speed of the sounds is 
The distance of the first source from the point considered is 
The distance of the second source from the point considered is 
Generally the phase angle made by the first sound wave at the considered point is mathematically represented as
![\phi_a = 2 \pi [\frac{a}{\lambda} + ft]](https://tex.z-dn.net/?f=%5Cphi_a%20%3D%20%202%20%5Cpi%20%5B%5Cfrac%7Ba%7D%7B%5Clambda%7D%20%20%2B%20ft%5D)
Generally the phase angle made by the first sound wave at the considered point is mathematically represented as
Here b is the distance o f the first wave from the considered point
Gnerally the phase diffencence is mathematically represented as
=> ![\Delta \phi = \frac{2\pi [ a - b]}{ \lambda }](https://tex.z-dn.net/?f=%5CDelta%20%20%5Cphi%20%20%20%3D%20%20%20%5Cfrac%7B2%5Cpi%20%5B%20a%20-%20b%5D%7D%7B%20%5Clambda%20%7D)
Gnerally the wavelength is mathematically represented as

=> 
=> 
=> ![\Delta \phi = \frac{2* 3.142 [ 4.40 - 4.0 ]}{ 0.611 }](https://tex.z-dn.net/?f=%5CDelta%20%20%5Cphi%20%20%20%3D%20%20%20%5Cfrac%7B2%2A%203.142%20%5B%204.40%20-%204.0%20%5D%7D%7B%20%200.611%20%20%7D)
=> 
<span>If your speed changes from 10 km/h to 6 km/h, you have a negative acceleration. The correct option among all the options that are given in the question is the first option or option "a". The other choices are totally incorrect. I hope that this is the answer that has actually come to your help.</span>
You use a force meter to measure newtons