A block with a mass $m=4\mathrm{.}0kg$ is suspended from a nonlinear spring.

Consider three different springs:

A linear spring, $f_s=k_{1}x.$

A nonlinear hardening spring, $f_s=k_{1}x+k_2{x}^3.$

A nonlinear softening spring, $f_s=k_{1}x-k_2{x}^3.$

Where $k_1=5\frac{N}{m}m$ and $k_2=\mathrm{.}01\frac{N}{m}{m}^3.$

Write a single MatLab program which:

a$)$ Plots the spring force $f_s$ for each spring $(x_{0}g-15mm$

Please Use MatLab!!! Answers are provided