What is Hooke's Law?

Its a simple statement that the extension (e) of an elastic material is directly proportional to the Force (F) that's put on it. This allows us to predict exactly how much something behaves when put under a load. k is the spring constant and depends on the material used.

F (N) = k . e (m)

Hooke’s Law states that:

The extension of an elastic object is directly proportional to the force applied, up to the limit of proportionality.

Directly proportional means that as more force is applied, the greater the extension (and vice versa)

The limit of proportionality is where if more force is added, the object may extend but will not return to its original shape when the force is removed (it will be inelastically deformed)