In physics, a force is a vector magnitude that expresses an action that is printed on an object in a state of motion or rest. This action involves a change in speed, direction or shape. Its name comes from the Latin fortia.

According to the definition of force, it acts on an object that is capable of modifying its acceleration, that is, varying its speed and its trajectory. A force can also cause the deformation of an object and a change in pressure.

In addition to its magnitude and direction, a force is determined by the point of application where it acts on a body.

If the sum of all the forces on a body is zero, then the center of mass is not accelerated. The body can deform under the influence of these forces. For example, the body can stretch due to two opposing forces.

The unit of measure for force in the international system of units is Newton (N).

## Newton's Laws

Newton's laws are the foundations of mechanics and dynamics that Sir Isaac Newton raised from the works of Galileo Galilei.

First Law: If there is no resultant force acting on an object, the object will not change its speed.

Second law: a resultant force involves a change in motion in an object and therefore an acceleration proportional to its mass. For example, the force of gravity implies an acceleration of 1 m / s2 to an object in free fall.

Third Law: the force that acts between two objects is always mutual, with opposite directions.

## Types of Forces

The concept of force is a phenomenon caused by the interaction between particles. There are dozens of types of forces but according to the standard model of particles, all of them can be reduced to one of the following four fundamental forces:

The electromagnetic force.

The strong nuclear force.

The weak nuclear force.

The force of gravity.