+ and - Stability/ Unstability -Repulsion Like charges (repulsive force): and the equilibrium point is always STABLE. i.e. fluctuation to left (x<5) and +ve force pushes to right (toward x=5), conversely fluctuation to right (x>5) and -ve force pushes to left (toward x=5). Document Title/Description
+ and - Stability/ Unstability -Attraction Unlike charges (attractive force): and the equilibrium point is not always STABLE. For too weak a spring (upper) fluctuation to left (x<5) and -ve force pushes to left AWAY from the force balance point –UNSTABLE. For a stronger spring (lower) fluctuation to left (x<5) and +ve force pushes to right toward the force balance point –STABLE.