[tex]dane:\\v = 18\frac{m}{h} = 18\cdot\frac{1000 \ m}{3600 \ s} = 5\frac{m}{s}\\\frac{T}{2} = 3,14 \ s \ \ \rightarrow \ \ T = 2\cdot3,14 \ s\\szukane:\\r = ?\\\\Rozwiazanie\\\\v = \frac{2\pi r}{T} \ \ /\cdot T\\\\2\pi r = vT \ \ /:2\pi\\\\r = \frac{vT}{2\pi}\\\\r = \frac{5\frac{m}{s}\cdot2\cdot3,14 \ s}{2\cdot3,14} = 5 \ m[/tex]
Odp. Promień okręgu r = 5 m.
