Answer: D. 0.57
Explanation:
The formula to calculate the eccentricity
of an ellipse is (assuming the moon's orbit in the shape of an ellipse):

Where:
is the apoapsis (the longest distance between the moon and its planet)
is the periapsis (the shortest distance between the moon and its planet)
Then:


This is the moon's orbital eccentricity
Answer:

Explanation:
Given that
The speed of the airplane ,v= 142 m/s
The speed of the air ,u = 30 m/s
Lets take angle make by airplane from east direction towards north direction is θ .
Now by using diagram ,we can say that

Now by putting the values in the above equation we get



Therefore the angle will be 12.19° .
b. 460.8 m/s
Explanation:
The relationship between the speed of the wave along the string, the length of the string and the frequency of the note is

where v is the speed of the wave, L is the length of the string and f is the frequency. Re-arranging the equation and substituting the data of the problem (L=0.90 m and f=256 Hz), we can find v:

c. 18,000 m
Explanation:
The relationship between speed of the wave, distance travelled and time taken is

where
v = 6,000 m/s is the speed of the wave
d = ? is the distance travelled
t = 3 s is the time taken
Re-arranging the formula and substituting the numbers into it, we find:
