a) d(BC)=v*t=30m/s*20min=30m/s*1200s=36000m
v=d/t
b) pentru a afla timpul necesar masinii pentru a ajunge din orasul B in or. D calculam: t=d/v=75600m/24 m/s=3150 s (timpul parcurs din or C pina in or.D)
t (BD) =t (BC)+t (CD) =1200s+3150s=4350s
c) t total= t (AB)+ t (BC+CD)=1/4h+4350s=900s+4350s=5250s=1h46 min
findca porneste la ora 8 si parcurge distanta pina in D in 1h46min rezulta ca ajunge la ora 9si 46 min
d ) v med= d tot/t tot= 129600m/5250s =24.69 m/s
d (AB)= v*t=72km/h*1/4h=18km=18000m
d tot =18000m+36000m+75600m=129600 m