Once tapped with a rubber hammer, the tines of a tuning fork begin vibrating. A computer-interfaced microphone detects
the resulting vibrations of the surrounding air, providing the
plot of pressure as a function of time. Consider the two cases
below. In which case does the tuning fork have the greatest
frequency?
Case A
Case B
401
40
20
20
Pressure Dev'n (dB)
Pressure Dev'n (dB)
0
0
ot
time
0.1
time
-20
-20
-40
-40
The case with the greatest frequency is Case: Tap Me!

d. learned preferences i believe is your answer

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me