Answer: The magnitude of the fore of asteroid A on asteroid B is equal to the magnitude of the force of asteroid B on asteroid A.
Explanation:
The force of one asteroid on the other, is explained by the Universal Law of gravitation, that can be written as follows:
Fg = G* mA*mB / (rAB)²
Even though the force is a vector, and is directed towards one of the masses, along the line that joins their centers, it can be seen the magnitude is the same.
This can be explained also stating that these forces form a pair of action-reaction forces, which, according with Newton’s 3rd Law, must be equal and opposite each other.