Question

DAU CORRRROANA: Doua automobile pornesc din aceeasi localitate in sensuri opuse cu viteza de 54 km/h si respectiv,72 km/h.Care va fi distanta dintre ele peste o ora?

Answer 1

$v_1=54 \ km/h \\ v_2=72 \ km/h \\ t=1 \ h \\ \boxed{\triangle d-?} \\ \bold{Rezolvare:} \\ \boxed{v= \frac{d}{t} } \\ \Rightarrow d=v \cdot t \\ \Rightarrow \triangle d=d_2-d_1 \\ d_2=v_2 \cdot t \\ \Rightarrow d_2=72 \ km/h \cdot 1 \ h=72 \ km \\ d_1=v_1 \cdot t \\ \Rightarrow d_1=52 \ km/h \cdot 1 \ h=54 \ km \\ \Rightarrow \triangle d=72 \ km-54 \ km \\ \Rightarrow \boxed{18 \ km}.$

Answer 2

v1=54km/h;
v2=72km/h;
⇒v=18km/h;
⇒Δd=v·Δt;
⇒Δt=1h;
⇒Δd=18km/h ·1h⇒se reduce h[ora] cu h[ora] si va ramane km[kilometru];
⇒Δd=18km⇒distanta dintre cele dua automobile peste o ora;