He stated his observation as "Ut tensio, sic vis" - - As the extension, so is the force. This linear elastic response has been formalized into the stress/strain relationship known as Hooke's Law: ...

The extension is the new length minus the unloaded length. Figure caption, Graph showing Hooke's Law, force is plotted against extension Provided that the limit of proportionality is not exceeded ...

Professor Brian Cox highlights the effect of forces in changing the shape of an object. Hooke’s Law is described using the example of a spring.