[tex]dane:\\v = 45\frac{km}{h} = 45\cdot\frac{1000 \ m}{3600 \ s} = 12,5\frac{m}{s}\\s =15 \ m\\g = 10\frac{m}{s^{2}}\\szukane:\\f = ?\\\\Rozwiazanie\\\\E_{k} = W\cdot s\\\\\frac{mv^{2}}{2} = T\cdot s\\\\ale\\\\T = m\cdot g\cdot f\\\\czyli:\\\\\frac{mv^{2}}{2} = m\cdot g\cdot f\cdot s \ \ /:mgs\\\\f = \frac{\frac{v^{2}}{2}}{g\cdot s}\\\\f=\frac{v^{2}}{2gs}\\\\f = \frac{(12,5\frac{m}{s})^{2}}{2\cdot10\frac{m}{s^{2}}\cdot15 \ m}=\frac{156,25\frac{m^{2}}{s^{2}}}{300\frac{m^{2}}{s^{2}}}\\\\f = 0,52[/tex]
