[tex]dane:\\t = 15 \ min = 15\cdot 60 \ s = 900 \ s\\\Delta v = 50\frac{km}{h} = 50\cdot\frac{1000 \ m}{3600 \ s} = 13,(8) \ \frac{m}{s} = 13,89\frac{m}{s}\\szukane:\\a = ?\\\\a = \frac{\Delta v}{t}\\\\a = \frac{13,89\frac{m}{s}}{900 \ s}\\\\a = 0,015\frac{m}{s^{2}}[/tex]