Equilibrium
Equilibrium is defined as the state at which opposing forces or influences are balanced. In physics, this translates into the moment in time when the net forces on the chosen system are zero. A system, if not acted upon, will approach equilibrium, according to Newton's First Law of Motion.
The Main Idea
Equilibrium is important in physics because it describes a specific scenario in which the system's net forces have reached zero. When a system is in equilibrium, the system will have reached its final state, and future predictions about the system can be made, assuming nothing happens to the system to knock it back out of equilibrium. Equilibrium is a beautiful concept because nature revolves around the concept of the natural state, and many problems can be made much simpler when a system has reached its equilibrium.
Equilibrium applies to both physical systems with momentum, and energetic systems. A net force of zero on the chosen system is considered to be a system that has reached its equilibrium point.
A Mathematical Model
The Mathematical equation that is most frequently used to Describe equilibrium is Fnet which is the sum of all forces is equal to zero. This means that all forces that would be acting on your chosen system have either stopped acting on it, or have reached the same magnitude as another force equal in magnitude but opposite in its direction.
A Computational Model
There are plenty of computational models that can be used to model different kinds of equilibria such as Physical equilibria , and chemical equilibria, amongst others. For a more in depth look at the different classes of computational models that can be used to calculate exact points of equilibria visit [1]
Connectedness
Industrial applications of equilibria are everywhere, but especially in Chemical Plants. Chemical Plants frequently like to keep their reacting materials in equilibrium, that way it is easier to predict what is going to happen when those materials react, especially at a large scale. Keeping a running system in equilibrium is known as continuous steady state in the field of Chemical Engineering.
History
Equilibrium is a concept that has been around for a long time, starting first as an idea in ancient religions, that sought equilibrium between a person's soul and the spirit world, or the world of deities. E
Equilibrium is a driving force and is explained best by Le Chatliers Principle. Le Chatliers says that a system at a non-equilibrium state will adjust for the new conditions and move towards a new equilibrium.
See also
Potential Energy that explains all about how system gain the energy to move towards equilibrium [2]
Further reading
For a list of articles that involve equilibrium in chemical systems here is a link [3]
References
A great flowchart about different topics in physics [4] Chabay, Ruth W., and Bruce A. Sherwood. Matter & Interactions. Hoboken, NJ: Wiley, 2011. Print.