A force is an action applied to an object. As a consequence of the force, the object may move, change shape or any other characteristic of the body. Forces are classified accordingly with the following guides:
Most of the forces study in these notes are contact forces.
In the international system of measurement, the unit of force is the Newton (N). The Newton is not a fundamental unit of measurement, it is derived from the meter, kilogram, and second. In fact,
The most important characteristic of forces is that they are vectors. As such, forces have magnitude and direction, ; graphically, forces are represented by arrows. The symbols to represent forces are the same as those to represent any other vectors, .
Algebraic operations between forces follow the rules for vector's operations. In particular, the vector addition rules apply to forces. The following diagram illustrate the basic steps for obtaining the result of applying different forces over an object.
When several forces act on an object, the vector addition of these forces is called the net force, .
If the vertical force is 4 N and
the horizontal force is 3 N; then the net force is
3 N; then the net force is