$${\mathtt{v}} = {\mathtt{g}}{\mathtt{\,\times\,}}{\mathtt{t}}$$ ; $${\mathtt{s}} = {\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{\mathtt{g}}{\mathtt{\,\times\,}}{{\mathtt{t}}}^{{\mathtt{2}}}$$ => $${\mathtt{t}} = {\sqrt{{\frac{{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{h}}}{{\mathtt{g}}}}}}$$ ;$${\mathtt{t}} = {\sqrt{{\frac{{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{s}}}{{\mathtt{g}}}}}}$$
$${\mathtt{v}} = {\sqrt{{\mathtt{2}}{\mathtt{\,\times\,}}{\mathtt{g}}{\mathtt{\,\times\,}}{\mathtt{h}}}}$$
http://physiknerd.de/freier-fall-online-rechner/
http://jumk.de/kombinatorik/binomialkoeffizient.php