হুকের নীতি

Hooke's Law relates the restoring force of a spring with its spring constant $k$ and the displacement from equilibrium $\Delta x$.

A spring will always want to be in equilibrium. When the spring is stretched, the spring force will point in the direction of equilibrium, away from the applied force. When the spring is compressed, the spring force will point in the direction of equilibrium once again, away from the applied force.

Therefore, Hooke's Law states:

$$F = - k \cdot \Delta x.$$