Hooke's law states that the strain of the material is proportional to the applied stress within the elastic limit of that material.

F = -kx

F = force exerted by the spring. Unit: N

-k = Springs constant. unit: N/m

x = Displacement of the object. Unit: m

Spring constant is always negative because the force of the spring is always opposite to the direction of the movement of the object.

Elastic potential energy

(1/2)kx^2

Elastic Limit: If the force exceeds a certain limit, the material will not return to its original shape (plastic deformation occurs).

Applications: Used in springs, shock absorbers, measuring devices (spring scales), and engineering structures.

Limitations: Does not apply to materials beyond their elastic limit or in highly deformed states (like rubber or plastic).