[tex]dane:\\v_{o} = 0\\h = 9 \ m\\g = 10\frac{m}{s^{2}}\\szukane:\\v = ?\\\\Rozwiazanie\\\\Z zasady \ zachowania \ energii\\\\E_{p} = E_{k}\\\\mgh = \frac{mv^{2}}{2} \ \ /\cdot\frac{2}{m}\\\\v^{2} = 2gh\\\\v = \sqrt{2gh}\\\\v = \sqrt{2\cdot10\frac{m}{s^{2}}\cdot9 \ m}\\\\v = \sqrt{180\frac{m^{2}}{s^{2}}}}=\sqrt{36\cdot5} \ \frac{m}{s} = 6\sqrt{5} \ \frac{m}{s}\\\\v\approx13,42\frac{m}{s}[/tex]
