Answer A is incorrect
A crest is just one point. It is not the distance between 2 crests.
B is incorrect
A trough is just 1 point. It is not the distance between 2 troughs.
C is incorrect.
the amplitude measures the height of a crest from the middle of the wave to the crest (or trough).
D is the correct answer. That is the distance between 2 crests or 2 troughs
Trust me, i'm a k12 student and its motor
Explanation:
The given data is as follows.
m = 5000 kg, h = 800 km = 
, r = R + h = 
kg, G = 
As we know that,

v = 
And, it is known that formula to calculate angular velocity is as follows.

v = 
= 
= 
Thus, we can conclude that speed of the satellite is
.
Answer:
Sound intensity is the amount of energy carried by sound versus loudness is a subjective measurement of the audible sound.
Sound intensity is measured in watt per square meter where loudness is measured in sones (sone is a subjective measurement and not an SI unit)