function domet=strel(smodnik,ocena)
v=smodnik*[1,1]/sqrt(2); beta=2; g=9.80665;
x='v(1)/beta*(1-exp(-beta*t))';
y='1/beta^2*(g-beta*g*t+beta*v(2)-exp(-beta*t)*(g+beta*v(2)))';
t=ocena;
eps=1e-8;
for i=1:100,
        ff=eval(y);
        tt=t(2)-ff(2)*diff(t)/diff(ff);
        t(1)=t(2); t(2)=tt;
        if abs(diff(t))<eps, break, end;
end;
t=mean(t);
domet=mean(eval(x));

