Discuss how a "restoring force" and an "equilibrium position" are related? (simple explanation please!)

For a periodic motion, say simple harmonic motion, the restoring force is defined as the force responsible for pulling the body under motion back towards the equilibrium position. Whereas the equilibrium position is defined as the position where the body under motion has no force acting on it, and it is in state of equilibrium.

As depicted above, the equilibrium is the position of x = 0 while the restoring force is the force pulling the block back towards the equilibrium position.

For a simple hamonic motion, restoring force = F = -kx where k is the spring constant and x is the displacement from the equilibrium position.

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