Answer:
= 4.688 106 m
Explanation:
The expression for the center of mass is
R cm = 1 / M ∑

Where M is the total mass of the system, ri and m1 are the distance and mass of each particle from a defined origin
Let's look for the total mass, the mass of the moon is m and that of the earth Me
M =
+ m
M = 81m + m
M = 82 m
The distance from the earth to the moon is R = 384.4 106 m
= 1 / M (M R1 + m R)
= 1 / 82m (0 + m R)
= R / 82
= 384.4 106/82
= 4.688 106 m
The radius of the earth is
= 6371 103 m
= 6.371 106 m
We can see that the center of mass of the system is within the beating radius
The energy emitter from the sun comes from the burning of hydrogen gasses (what the entire sun is made of) allowing light and heat energy to be created/escape.
Acceleration= change in velocity/ change in time.
60-40=20 m/s (change in speed)
Time= 8 seconds
20/8= 2.5
Acceleration= 2.5 m/s^2
Hope this helps! :)
There are no correct formulas on the list you provided.