Answer:
Phenomena is the plural form of Phenomenon.
A phenomenon is an extraordinary occurrence or circumstance.
Magma, first, outer layer, inner layer
Answer:
The number of revolutions turned by the centrifuge is 8250 revolutions.
Explanation:
Given;
number of revolution per minutes, ω = 15000 rpm
time of motion, t = 330 s = 5.5 minutes
The number of revolutions turned by the centrifuge is given by;

Therefore, the number of revolutions turned by the centrifuge is 8250 revolutions.
Answer: observed frequency (f') = 511.97Hz
Explanation: when there is a relative motion between an observer and a sound source, the frequency of sound wave perceived by the observer is different from the frequency of originally sent out by the sound source.
This is called Doppler effect and given mathematically below as
f' = (v + v') /(v- vs) * f
f' = observed frequency
v = speed of sound in air = 340m/s
v' = velocity of observer= 45m/s
vs = velocity of source relative to observer = - 36m/s ( the negative sign came as a result of the fact that the velocity of the source is in opposite direction to the velocity of the observer)
f = original frequency of sound source = 500Hz
f' = (340 + 45)/{340 -(-36)} * 500
f' = 385/ (340 + 36) * 500
f' = 385/ 376 * 500
f' = 1.0239 * 500
f' = 511.97Hz