[tex]dane:\\l = 3 \ m\\g = 10\frac{m}{s^{2}}\\szukane:\\T = ?\\f = ?\\\\T = 2\pi\sqrt{\frac{l}{g}}\\\\T = 2\cdot3,14\cdot\sqrt{\frac{3 \ m}{10\frac{m}{s^{2}}}}\\\\T = 6,28\cdot\sqrt{0,3} \ s\\\\T = 6,28\cdot0,5477 \ s\\\\\boxed{T = 3,4 \ s}\\\\\\f = \frac{1}{T}\\\\f = \frac{1}{3,4 \ s}\\\\\boxed{f = 0,3 \ Hz}[/tex]
