A condition in which all influences acting cancel each other, so that a static or balanced situation results. In physics, equilibrium results from the cancellation of forces acting on an object.

 

In physical sense: The condition of equal balance between opposing forces; that state of a material system in which the forces acting upon the system, or those of them which are taken into consideration, are so arranged that their resultant at every point is zero.
A body is said to be in stable equilibrium, when it returns to its original position after being disturbed; in unstable when it continues to move in the direction given to it by the disturbing force; in neutral, when it remains stationary in its new position.

If the equilibrium is stable , the potential energy of a system is a minimum , and the equilibrium is unstable if the potential energy is a maximum.

Equilibrium, in physics, the condition of a system when neither its state of motion nor its internal energy state tends to change with time. A simple mechanical body is said to be in equilibrium if it experiences neither linear acceleration nor angular acceleration; unless it is disturbed by an outside force, it will continue in that condition indefinitely. For a single particle, equilibrium arises if the vector sum of all forces acting upon the particle is zero.

The condition of equilibrium has two requirements:

• All forces balance. This means that force vectors add to zero.
• All torques balance around any point. This means that the sum of all clockwise and counterclockwise torques is zero.

When analyzing torques, you can pick any point as the axis because the entire object is not rotating. Usually, you pick the point where an unknown force acts so that this force contributes zero torque to the torque equation.

Hope this helps.

A condition in which all influences acting cancel each other, so that a static or balanced situation results. In physics, equilibrium results from the cancellation of forces acting on an object.
It refers to a point in space (or a value of a field) at which the potential energy is at a local maximum or minimum. For the case of objects in space, this translates to a net force of zero, since force is proportional to the slope of the potential energy curve.