[tex]dane:\\T = 2 \ s\\g = 9,81\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\\\\gT^{2} = 4l\pi^{2} \ \ /:4\pi^{2}\\\\l = \frac{gT^{2}}{4\pi^{2}}\\\\l = \frac{9,81\frac{m}{s^{2}}\cdot(2 \ s)^{2}}{4\cdot3,14^{2}}=\frac{39,24}{39,4384} \ m\\\\l \approx 1 \ m[/tex]
