The tension in the string B) It quadruples.
Explanation:
The ball is in uniform circular motion in a horizontal circle, so the tension in the string is providing the centripetal force that keeps the ball in circular motion. So we can write:

where:
T is the tension in the string
m is the mass of the ball
v is the speed of the ball
r is the radius of the circle (the lenght of the string)
In this problem, we are told that the speed of the ball is doubled, so
v' = 2v
Substituting into the previous equation, we find the new tension in the string:

Therefore, the tension in the string will quadruple.
Learn more about circular motion:
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Answer:
The speed is 24 
Explanation:
A wave is a disturbance that propagates through a certain medium or in a vacuum, with transport of energy but without transport of matter.
The wavelength is the minimum distance between two successive points of the wave that are in the same state of vibration. It is expressed in units of length (m).
Frequency is the number of vibrations that occur in a unit of time. Its unit is s⁻¹ or hertz (Hz).
The speed of propagation is the speed with which the wave propagates in the middle, that is, the magnitude that measures the speed at which the wave disturbance propagates along its displacement. Relate wavelength (λ) and frequency (f) inversely proportionally using the following equation:
v = f * λ.
In this case, λ= 8 meter and f= 3 Hz
Then:
v= 3 Hz* 8 meter
So:
v= 24 
<u><em>The speed is 24 </em></u>
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The air would contract therefore the answer is the second choice.
Magnetic fields are an area around a magnetic material or a moving electric charge with which the force of magnet