Answer:
The decibel of the remaining pigs is 51.5 dB.
Explanation:
Decibel (dB) is a unit of measure of the intensity of a given sound.
Number of pigs = 199, noise level = 74.3 dB.
Given that the intensity (I) of the sound from the pen is proportional to the number of pigs (N), thus:
I
N
I = kN
where k is the constant of proportionality.
⇒ k = 
= 
k = 0.3734
When 61 numbers of pigs were removed, the number of remaining pigs (N) squealing at their original level is 138.
Thus, the becibel level (I) of the remaining pigs can be determined by:
I = kN
= 0.3734 × 138
= 51.53 dB
The becibel level (I) of the remaining pigs is 51.53 dB.
"Multiple accelerations" is a puzzling phrase, and I'd be curious to understand it
better. Sadly however, you haven't explained it at all.
If the multiple accelerations are the accelerations of multiple objects, then
the net force on each object is the product of (its mass) x (its acceleration).
If the multiple accelerations are the acceleration of one object at different times,
then at any instant of time, the net force on the object is the product of (its mass) x
(its acceleration at that instant).
The frequency of a sound wave is the number of cycles of a sound wave per second or Hertz (Hz). The frequency can be calculated by dividing wavelength by time (Figure 1.3). A small wavelength will yield a higher frequency, whereas a larger wavelength will yield a smaller frequency.
I think it might be D but I am not sure