[tex]dane:\\s_1 = 120 \ m\\t_1 = 2 \ min = 120 \ s\\s_2 = 60 \ m\\t_2 = 60 \ s\\szukane:\\v_{sr} = ?\\\\Rozwiazanie\\\\v_{sr} = \frac{s_{c}}{t_{c}}\\\\s_{c} = s_1 + s_2 = 120 \ m + 60 \ m = 180 \ m\\\\t_{c} = t_1 + t_2 = 120 \ s + 60 \ s = 180 \ s\\\\v_{sr} = \frac{180 \ m}{180 \ s} = 1\frac{m}{s}[/tex]
Odp. Średnia prędkość piechura to 1 m/s.