Two objects attract each other gravitationally. if the distance between their centers increases by a factor of 3, and both of the objects' masses increase by the same factor, how does the gravitational force between them change? a) the gravitational force decreases by a factor of 3.
b) the gravitational force increases by a factor of 3.
c) the gravitational force decreases by a factor of 9.
d) the gravitational force increases by a factor of 9.
e) the gravitational force remains unchanged.