The strength of the gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. This is described by Newton's Law of Universal Gravitation:

F = G * (m1 * m2) / r²

Where:

* F is the force of gravity

* G is the gravitational constant (approximately 6.674 x 10⁻¹¹ N⋅m²/kg²)

* m1 and m2 are the masses of the two objects

* r is the distance between the centers of the two objects

Let's break down the relationship:

* Mass: The more massive the objects, the stronger the gravitational force between them. This makes sense intuitively – the Earth has a much stronger gravitational pull than a small rock, even at the same distance.

* Distance: As the distance between the objects increases, the gravitational force decreases rapidly. This is because the force is inversely proportional to the square of the distance. Doubling the distance reduces the force to one-fourth its original value.

Here are some examples:

* Planets and their moons: The Moon is held in orbit around the Earth due to the Earth's gravitational pull. The Earth's mass is much greater than the Moon's, so the force of gravity is significant enough to keep the Moon in orbit.

* Apples falling from trees: The apple falls to the ground due to Earth's gravity. The Earth's mass is far greater than the apple's, creating a strong enough force to pull the apple towards it.

* The Sun and the planets: The Sun's massive size exerts a strong gravitational pull on all the planets in our solar system, keeping them in orbit.

In summary: The strength of the gravitational force depends on both the masses of the objects and the distance between them. More mass means a stronger force, while greater distance means a weaker force. This fundamental law governs the motion of celestial bodies and the interactions of everyday objects.