Răspuns:
Explicație:
1. v = d : t
d = vt
v = 10 m/s
t = 3 min = 3 x 60 = 180 s
distanta pana la prieten = 10 m/s x 180 s = 1800 m
2. v = d : t = 1800 m : ( 2 x 60s ) = 1800 m : 120 s = 15 m/s
3. viteza medie = distanta totala : timp total
distanta totala = 1800 m + 1800 m = 3600 m
timp total = timp dus + pauza + timp intors
timp total = 3 min + 2 min + 2 min = 7 min = 7 x 60 = 420 s
vm = 3600 m : 420 s = 8,57 m /s