An 12 kg mass and a 18 kg mass experience a force of gravity pulling the balls towards each other of 4.7 x 10^-10 N. What is the separation distance of the two masses?

Explanation:

We can use Newton's Universal Law of Gravitation to solve this:

,

Plugging in given values, we have the equation:

.

Solving, we get:

.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.