Equilibrium concepts

Equilibrium is the condition where the null force applied to an object is zero
The static equilibrium is when if a body is in rest in relation to a referencesystem.
The center of gravity in an object is the point in relation to where the forces that act in the different points of the materials that form an object produce amomentum equal to zero.
There are three classes of static equilibrium: stable, unstable and indifferent.
Stable equilibrium: an object is found in stable equilibriumwhen an external agent pull it out momentarily of its original equilibrium and this body will return to its original configuration by gravity forces.
Unstableequilibrium: an object is found in unstable equilibrium when an external agent pulls it out of its original equilibrium and it moves away from its original configuration.Indifferent equilibrium: an object is found in an indifferent equilibrium when an external agent pulls it out momentarily of its original equilibrium and this does notpresent a tendency of returning nor getting away from its original state.
Translational equilibrium
An object is found in translational equilibrium when thesumatory of all of the components in x is equal to 0 and all the components of y are equal to 0
Tension T: is the force that can exist from an interaction in a rope orcable when it is attached to a body and this is tensionated or pulled
A body is found in rotational equilibrium if the resultant momentum (torque t) of all the forcesacting against it, in relation to any point, is null.
Force of Momentum (mf) : Vectorial product of the position vector r of the force by the force vector F.