Which statement correctly reflects the balance of forces in an equilibrium system?

In an equilibrium system, the defining characteristic is that all forces acting on the system are balanced. This means that when considering the forces applied to the system, the sum of the forces acting in one direction must equal the sum of the forces acting in the opposite direction.

When the total forces to the right equal the total forces to the left, there is no net force acting on the system. This condition ensures that the system remains stable and does not move or rotate in any direction. If the forces were imbalanced in any way, the system would either rotate or move, rather than maintaining equilibrium.

In this context, the other statements suggest motion or vibration, which would only occur if there were a net force causing such action. At equilibrium, however, the system is at rest, confirming that the balance of forces condition is fulfilled.