Moving the bead to the opposite side of the trap flips the sign of both displacement and force, so the restoring arrow now points the other way. With the bead at -2 m the displacement is -2 - 0 = -2 m, and stiffness 2 N/m gives force magnitude 2 times 2 = 4 N pointing toward positive position exactly for the stated toy force ledger; real sign conventions need coordinate calibration, noise filtering, drift checks, and measurement uncertainty.
Moving the bead across the center flips the restoring direction. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
A bead on the other side changes the sign
The bead is at negative 2 metres, so its signed displacement is negative 2 metres.
−2−0=−2
The restoring arrow reverses direction
With the same stiffness 2 newtons per metre, the force magnitude is 4 newtons toward positive position.