Physics – 1.5.1 Effects of forces | e-Consult

(a) The region of the graph that shows the elastic behaviour is the straight line. This is the elastic region.

(b) When the material is loaded beyond the elastic limit, it undergoes plastic deformation. This means that the material will permanently change shape, and when the load is removed, it will not return to its original dimensions. The load-extension graph will show a steeper slope after the elastic limit.

(c) The gradient of the elastic region of the graph represents the stiffness of the material. A steeper gradient indicates a stiffer material, meaning it requires a larger force to produce a given extension. A shallower gradient indicates a less stiff material.