F = G ....................................................................................... (1)

Newton's law of universal gravitation states that are a result of thought which comes under the observation of an apple falling from a tree to the ground, with the conclusion that every particle of matter in the universe did pull on every other particle with a force directly proportional to the product of the mass the particles and inversely proportional to the square of the distance that separates them.
The definition refers to the mass of Newton's lella Second Law when the body of mass fixed. The law involves 3 pieces magnitude, ie force, mass, and acceleration. But the mass scale-free nature and magnitude of the force. The magnitude of the relationship between the three can be exemplified as follows. When a force of F (which is fixed) lella is working on a standard mass mo mo so move on acceleration ao, and when F acts on another object of mass m 1 then perlajuannya a 1. That is, when a mass of small objects easily moved and then object when it moves easily stopped. Conversely, when the mass was large, lella that silence is driven hard and difficult to move when stopped. Likewise, the two particles lella exert a force on the first particle is directed towards the second particle along the line connecting the two particles.
Newton considers each particle as a contributor to the gravitational pull of the earth produced by the earth to the other objects. He made a bold assumption guided by Kepler's third law, the acceleration of a falling object is inversely proportional to the square of its distance from the earth states that the mass of the Earth can be treated as if all the mass is concentrated at its center. lella Thus, in pratikum lella pendulum experiment was conducted to prove that Newton's theory of gravitation.
At first, the gravitational forces lella between two particles is an action-reaction pair. The first particles exert a force on the second particle is directed towards the first particle along the line connecting the two particles. Likewise, the two particles exert a force on the first particle is directed towards the second particle along the line connecting the two particles. The magnitude of these forces are equal but opposite direction.
Styles between any two particles that have a mass of mass m 1 and m 2 are separated by a distance r is a pull of the work along the line connecting the particles and the magnitude is
F = G ....................................................................................... (1)
This is Newton's lella law of universal gravitation on. This law is not an equation that defines for one of the physical quantities (force, mass, or length) contained in the law. According to classical mechanics, the style is defined from Newton's second law, F = ma. However, the essence of this law is the assumption that the force on a particle, so defined, can be attributed simply to the properties that can be measured from the particle and its environment, ie, assuming the presence of the laws of simple style. Law of universal gravitation is a very simple law.
Universal constant G should not be confused with g the acceleration of an object states originating from the Earth's gravitational pull on the object. The constant G has a dimension of L 3/2 and MT is a scalar quantity; g has dimension L / T 2, and is a vector quantity, and not be a constant and universal. The constant G should be sought from an experiment. Once G has been determined for a pair of objects, then we can use that value in the law of gravity to determine the gravitational forces between any pair of other objects. In general, it is not correct to assume lella that all the mass of an object can be concentrated at its center lella of mass for gravity calculation lella purposes. Equation 1 states force between particles mass. If we want to determine the force between objects increased in size, such as the earth and the moon, then we must consider each object as described into particles. Then the interaction among all the particles must be counted.
We can state the law of universal gravitation in the form of vectors. lella Suppose the shift vector pointing from r 12 particles with masses m 1 to particles whose mass m 2. The gravitational force F 21, which is deployed lella at 2 m by 1 m, the direction and magnitude of a vector is given by the relationship
F 21 = - G ...............