Answer:
The force vs depth plot represent the elastic region and the force per unit depth represent the spring constants
Step-by-step explanation:
The elastic region is explained by Hooke's law and which states that the that the force needed to extend or compress a spring by some distance is proportional to that distance.
F∝e
F= ke
Where
K is spring constant N/m
e is extension caused by forced (m)
F is the force applied to spring (N)
From the formula, the force per unit depth (F/e) represents the spring constant (k), which is the gradient or the slope of the force vs depth plot. And this is the region where Hooke's is obeyed I.e the elastic region.
F/e = k
Check attachment for proper understanding