dane: s1 = 1/4 s v1 = 40 km/h s2 = 3/4 s v2 = 80 km/h szukane: vśr = ? vśr = s/t s1+s2 = (1/4 + 3/4)s = s t = t1+t2 t1 = s/4 :40 = s/4 *1/40 = s/160 [h] t2 = 3s/4 :80 = 3s/4 *1/80 = 3s/320 [h] t = s/160+3s/320 = 2s/320+3s/320 = 5s/320 = s/64 vśr = s : s/64 = s * 64/s vśr = 64 km/h =============
Dane: v₁= 40 km/h v₂= 80 km/h Szukane: vśr=? Rozwiązanie: v=s/t vt=s t=s/v t₁= 0,25s/40 km/h t₂= 0,75s/80 km/h [latex]v=frac{s}{t_1+t_2}[/latex] v=1 / 0,25/40 + 0,75/80 = 64 [km/h] Odp.: Średnia prędkość wynosi 64 km/h.
