Answer:
in general the largest mass M is located at the origin of the coordinate system.
Step-by-step explanation:
The law of universal gravitation is
F = G m M / r2
Newton's second law is
F = m a
Where the acceleration is centripetal
a = v² / r
Let's replace
G m M / r² = m v² / r
M = v² r / G
The value of r is the distance between the two masses in interest, in general the largest mass M is located at the origin of the coordinate system.
This is because the body with more mass moves less than the body