[tex]dane:\\v_{o} = 0\\v = 54\frac{km}{h} = 54\cdot\frac{1000 \ m}{3600 \ s} = 15\frac{m}{s}\\g = 10\frac{m}{s^{2}}\\szukane:\\t = ?\\\\Rozwiazanie\\\\Dla \ \ v_{o} = 0\\\\v = g\cdot t \ \ /:g\\\\t = \frac{v}{g}\\\\t = \frac{15\frac{m}{s}}{10\frac{m}{s^{2}}}\\\\t = 1,5 \ s\\\\Odp. \ B.[/tex]
