function unknownsDerivatives = Gallileo(t, unknowns,r)

% take the unknowns out og unknowns
s=unknowns(1);
v=unknowns(2);

% acc of grav
g=9.81;

rhoair=1.225;
area=pi*r^2;
CD=0.5;
rhoiron=7860;
m=rhoiron*4/3*pi*r^3;
FAir=CD*0.5*rhoair*v^2*area;

% find the ders of the unks
dsdt=v;
dvdt=g-FAir/m;

% ret unks ders
unknownsDerivatives=[dsdt dvdt]';

end

