[tex]Dane:\\T = 1 \ s\\g = 10\frac{m}{s^{2}}\\Szukane:\\l = ?\\\\Rozwiazanie\\\\T = 2\pi \sqrt{\frac{l}{g}} \ \ |^{2}\\\\T^{2} = 4\pi ^{2}\cdot\frac{l}{g} \ \ |\cdot g\\\\4\pi ^{2}l = T^{2}g \ \ /:4\pi ^{2}\\\\l = \frac{ T^{2}g}{4\pi ^{2}}\\\\l = \frac{(1 \ s)^{2}\cdot10\frac{m}{s^{2}}}{4\cdot3,14^{2}} = \frac{10}{39,4384} \ m\\\\\boxed{l\approx0,25 \ m}[/tex]
