The force of gravity decreases if two objects have

The force of gravity between two objects will decrease as the distance between them increases. The two most important factors affecting the gravitational force between two objects are their mass and the distance between their centers. As mass increases, so does the force of gravity, but an increase in distance reflects an inverse proportionality, which causes that force to decrease exponentially.

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i think the answer is a, hope this : )

+15-35=-20

going in opposite directions