[tex]Dane:\\v_{o} = 40\frac{km}{h} = 40\cdot\frac{1000 \ m}{3600 \ s} = 11,(1)\frac{m}{s}\approx11\frac{m}{s}\\v = 0\frac{m}{s}\\a = -2\frac{m}{s^{2}}\\Szukane:\\t = ?\\\\Rozwiazanie\\\\a = \frac{v-v_{o}}{t}\\\\ale \ \ v_{o} = 0\\\\a = \frac{-v_{o}}{t} \ \ \rightarrow \ \ t = \frac{-v_{o}}{a}\\\\t = \frac{-11\frac{m}{s}}{-2\frac{m}{s^{2}}}\\\\\boxed{t \appro=5,5 \ s}\\\\\underline{Odp. \ A.}[/tex]
