Stable equilibrium

Definition

Stable equilibrium occurs when a system, if displaced slightly, will return to its original position. This is due to the restoring forces or torques that act to bring the system back to equilibrium.

5 Must Know Facts For Your Next Test

1. The potential energy is at a minimum in stable equilibrium.
2. A system in stable equilibrium experiences restoring forces proportional to the displacement from equilibrium.
3. In diagrams, stable equilibrium points are often represented by valleys.
4. The second derivative of the potential energy function with respect to position is positive at points of stable equilibrium.
5. If perturbed, the oscillations around a stable equilibrium point are typically harmonic.

Review Questions

• What distinguishes stable equilibrium from unstable and neutral equilibrium?
• How can you identify a point of stable equilibrium using a potential energy curve?
• What role do restoring forces play in maintaining stable equilibrium?

Related terms

Unstable Equilibrium:

A state where any small displacement leads to forces that move the system further away from its original position.

Neutral Equilibrium:

A state where any small displacement neither restores nor diverts the system from its new position.

Restoring Force:

A force that acts to bring a system back to its equilibrium position.