[tex]Dane:\\v_{o} = 0\\h = 5 \ m\\g = 10\frac{m}{s^{2}}\\Szykane:\\t = ?\\\\Rozwiazanie\\\\h = \frac{gt^{2}}{2} \ \ \ |\cdot2\\\\gt^{2} = 2h \ \ \ /:g\\\\t^{2} = \frac{2h}{g}\\\\t = \sqrt{\frac{2h}{g}}\\\\t = \sqrt{\frac{2\cdot5 \ m}{10\frac{m}{s^{2}}}} = \sqrt{1 \ s^{2}}\\\\\boxed{t = 1 \ s}\\\\\underline{Odp. \ B}[/tex]