Wikipedia
Restoring force, in a physics context, is a force that gives rise to an equilibrium in a physical system. If the system is perturbed away from the equilibrium, the restoring force will tend to bring the system back toward equilibrium. The restoring force is a function only of position of the mass or particle. It is always directed back toward the equilibrium position of the system. The restoring force is often referred to in simple harmonic motion. The force which is responsible to restore original size and shape is called restoring force.
An example is the action of a spring. An idealized spring exerts a force that is proportional to the amount of deformation of the spring from its equilibrium length, exerted in a direction to oppose the deformation. Pulling the spring to a greater length causes it to exert a force that brings the spring back toward its equilibrium length. The amount of force can be determined by multiplying the spring constant of the spring by the amount of stretch.
Another example is of a pendulum. When the pendulum is not swinging all the forces acting on the pendulum are in equilibrium. The force due to gravity and the mass of the object at the end of the pendulum is equal to the tension in the string holding that object up. When a pendulum is put in motion the place of equilibrium is at the bottom of the swing, the place where the pendulum rests. When the pendulum is at the top of its swing the force bringing the pendulum back down to this midpoint is gravity. As a result gravity can be seen as the restoring force in this case.
Restoring Force is the third full-length studio album by American metalcore band Of Mice & Men. It was released on January 24, 2014 in Europe and Australia, January 27, 2014 in Japan and the UK and January 28, 2014 in the US through Rise Records. A deluxe edition of the album, titled Restoring Force: Full Circle, was released on February 20, 2015. It featured four bonus tracks, including an acoustic version of "Feels Like Forever".