Equilibrium
An object that has balanced forces on all sides is said to be in a state of equilibrium. This does not mean that all forces have to be equal on opposite sides. In the diagram below you can see how the forces up and down are not the same to the forces going left to right, but are still in a state of equilibrium
Objects that are in a state of equilibrium must have an acceleration of 0 m/s^2, but this does not mean that an object in equilibrium is always static. An object can be in equilibrium if it is moving with the same speed and direction.
Static Equilibrium
An object at rest and in the state of equilibrium is said to be in static equilibrium. In the image below, the weight being held on the string, is in static equilibrium because it is at rest and all the forces are balanced.
Equilibrium In Chemistry
Chemical Equilibrium is the when the reactants yield a product that has no net change in the reaction. Chemical Equilibrium is also known as a steady state reaction, where the reaction is happening but it has reached a balanced condition. Dynamic Equilibrium is when the products and reactants stay constant, while the reaction continues to happen.
Equilibrium in Everyday Life
The Forces of the two children balance because of the different radii between the smaller boy and larger girl
The stones are in static equilibrium because they are still and all the forces applied on the stones equal out.
The Carbon Cycle is an example of equilibrium because the carbon is moving at a constant rate from step to step throughout the cycle.
A car at a stop sign is in the state of Static Equilibrium
Sources:
http://www.physicsclassroom.com/class/vectors/Lesson-3/Equilibrium-and-Statics
http://chemistry.about.com/od/equilibrium/a/Chemical-Equilibrium.htm
http://www.physics.usyd.edu.au/super/life_sciences/FE/FE3.pdf
