What does it mean for an object to be in equilibrium?

An object is considered to be in equilibrium when it experiences no net force acting on it. This means that all the forces acting upon it are balanced, resulting in a state where the object either remains at rest or continues to move at a constant velocity. In essence, when the forces are balanced, there is no change in the object's state of motion according to Newton's First Law of Motion.

This state of equilibrium is essential in mechanics, as it ensures that there is neither acceleration nor deceleration occurring. Thus, specifically, when an object is either at rest or moving uniformly in a straight line, it is maintaining this condition.

In contrast to this, if an object is accelerating, experiences a net force greater than zero, or has a net force equal to its mass, it does not meet the criteria for equilibrium. Instead, it would be undergoing some form of change in motion. Understanding equilibrium is crucial for analyzing forces in static and dynamic systems effectively.