Răspuns:
Explicație:
1.v₁=9km/h=9.1000m/3600s=2,5m/s
v₂=18km/h=18.1000m/3600s=5m/s
v₃=27km/h=27.1000m/3600s=7,5m/s
t₁=20minute=20.60s=1200s
t₂=60minute=60.60s=3600s
t₃=20minute=1200s
2.d₁=v₁.t₁=2,5.1200=3000m
d₂=v₂.t₂=5.3600=18000m
d₃=v₃.t₃=7,5.1200=9000m
3.d=d₁+d₂+d₃=3000+18000+9000=30000m=30km
t=t₁+t₂+t₃=1200+3600+1200=6000s
4.vm=d/t=30000/6000=5m/s