modeling and simulation

السلام عليكم ورحمة الله وبركاته
im mufeed al-turk, im studying electrical engineering in jordan, i want to present important subject in this forum, it's modeling the systems and simulation using matlab, i start by an example about this subject, i want from everyone try to analayze any system that he wants and makes simulation for it
simple spring - mass


the previous fiqure displays a mass is attatched with asping on a rough surface , first we draw free body diagram to know variables and constants in the system ,



we can from the previous figure to extract wuation the we build up the simulation on it .
by newton's law
f(t)=m*a+B*v+K*x
where :
m: mass, B: frictional constant , K: spring constant
a: acceleration , x: displacement , v: velocity , f(t): external force
a=d^2x/dt^2 , v=dx/dt
so the equation will be :
f(t)=m*d^2x/dt^2 +B*dx/dt+K*x ,
now the simulation this model is :