There are two types of equilibrium: static equilibrium and dynamic equilibrium.
* Static equilibrium occurs when the object is not moving and the net force acting on it is zero. For example, a book sitting on a table is in static equilibrium.
* Dynamic equilibrium occurs when the object is moving but the net force acting on it is zero. For example, a car moving at a constant speed is in dynamic equilibrium.
All forces are zero when an object is in equilibrium because the forces acting on the object are balanced. This means that the forces acting in one direction are equal to the forces acting in the opposite direction. For example, if a book is sitting on a table, the force of gravity acting on the book is balanced by the force of the table pushing up on the book.
When all forces are zero, an object will remain in its current state of motion. If an object is at rest, it will remain at rest. If an object is moving, it will continue moving at the same speed and in the same direction.
