[tex]dane:\\h = 1 \ km = 1000 \ m\\g = \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\cdot1000 \ m\cdot10\frac{m}{s^{2}}} = \sqrt{20000\frac{m^{2}}{s^{2}}}=10\sqrt{2} \ \frac{m}{s}\\\\v \approx141\frac{m}{s}[/tex]
