Odpowiedź :
[tex]dane:\\v_{o} = 0\\t = 4 \ s\\s = 0,64 \ km = 640 \ m\\szukane:\\a = ?\\\\Rozwiazanie\\\\s = \frac{at^{2}}{2} \ \ |\cdot\frac{2}{t^{2}}\\\\a = \frac{2s}{t^{2}}\\\\a = \frac{2\cdot640 m}{(4 \ s)^{2}} = 80\frac{m}{s^{2}}[/tex]
[tex]dane:\\v_{o} = 0\\t = 4 \ s\\s = 0,64 \ km = 640 \ m\\szukane:\\a = ?\\\\Rozwiazanie\\\\s = \frac{at^{2}}{2} \ \ |\cdot\frac{2}{t^{2}}\\\\a = \frac{2s}{t^{2}}\\\\a = \frac{2\cdot640 m}{(4 \ s)^{2}} = 80\frac{m}{s^{2}}[/tex]