The gravitational force is a force that attracts any two objects withmass. The gravitational force isattractivebecause it always tries to pull masses together, it never pushes them apart. In fact, every object, including you, is pulling on every other object in the entire universe! This is called Newton's Universal Law of Gravitation. However, you don't have a very large mass and so, you're not pulling on those other objects much. Also, objects that are really far apart from each other don't pull on each other noticeably either. But the force is there!

Universal Gravitation Equation

The equation that describes the gravitational force between two bodies is the following:

F_G= G m₁m₂/r²

whereF_Gis thegravitational constant,Gis the gravitational constant,m₁andm₂are the masses of the two bodies, andr是他们的中心之间的距离。

The two masses,m₁andm₂, will exert the same gravitational force on each other.

Figure 1:The gravitational force between two objects of mass m₁and m₂separated by a distancer.

So if you know the masses of the two objects are and how far apart they are, you can calculate the gravitational force between them.

Notice that the distancer在堵塞om of the equation is squared. This makes it an inverse square law. Because of this, if you double the distance between two objects, you reduce the gravitational force between them to a quarter of what it was.

On the other hand, since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. So as the mass of either object increases, the force of gravitational attraction between them also increases.