Given data
*The given 4th harmonic frequency is 31.5 Hz
The fundamental frequency is calculated as

Hence, the fundamental frequency is 7.875 Hz
the electric force decreases because the distance has an indirect relationship to the force
Explanation:
The electric force between two objects is given by

where
k is the Coulomb's constant
q1 and q2 are the charges of the two objects
r is the distance between the two objects
As we can see from the formula, the magnitude of the force is inversely proportional to the square of the distance: so, when the distance between the object increases, the magnitude of the force decreases.
<span>The rate of change in velocity is acceleration.</span>
This is not something that waves do because they need a medium to travel through, while particles do not.
<h3>How light travels in space?</h3>
A light travels without any medium while on the other hand, a medium is required for sound waves to move from oe place to another. Sound is a mechanical wave that cannot travel through a vacuum.
So we can conclude that electromagnetic waves like light do not require medium for its propagation.
Learn more about light here: brainly.com/question/19697218