When two equal and opposite collinear forces are added, what happens to the equilibrium of the system?

When two equal and opposite collinear forces are added together, they create a situation where the effects of the forces cancel each other out. This phenomenon is rooted in the principles of static equilibrium, where an object is in a state of rest or uniform motion when the net force and net moment acting on it are both zero.

In this case, the equal magnitudes of the forces acting in opposite directions mean the net linear force is zero. As a result, there is no tendency for the object to move in either direction along that line. Consequently, the object remains in its state of equilibrium, which can be defined as a state where the sum of forces and the sum of moments about any point are zero.

This scenario illustrates a fundamental principle in engineering and physics, where balanced forces maintain equilibrium, highlighting why the correct choice reflects that the equilibrium of the system is maintained.