%MATLAB-funksjonen mfd.m
function xdot=mfd(t,x)
global m D Kf
u=4;
xdot(1)=x(2);
xdot(2)=-(Kf/m)*x(1)-(D/m)*x(2)+(1/m)*u;
xdot=[xdot(1);xdot(2)];