ta có:
S1-S2=340
\(\Leftrightarrow v_1t-v_2t=340\)
\(\Leftrightarrow136v_1-136v_2=340\)
\(\Leftrightarrow136v_1-68v_1=340\)
\(\Leftrightarrow68v_1=340\Rightarrow v_1=5\)
\(\Rightarrow v_2=2,5\)
ta có S1+S2=340m
=>v1t+\(\dfrac{v_1}{2}\)t=340
=>\(\dfrac{3v_1}{2}\)t=340
=>\(\dfrac{3v_1}{2}\).136=340
=>\(\dfrac{3v_1}{2}\)=2.5
=>v1=5/3km/h
=>v2=5/6km/h
câu dưới sai do mình ko đọc kĩ đề
ta có S1-S2=340
=>v1t-\(\dfrac{v_1}{2}\)t=340
=>\(\dfrac{1}{2}\)v1.136=340
=>\(\dfrac{1}{2}\)v1=2,5
=>v1=5m/s
=>v2=2,5m/s