Đáp án:
\(\begin{array}{l}
a.\\
{t_{di}} = 0,4h\\
b.\\
{v_{t/n}}' = 9,5\\
{t_{ve}} = \frac{2}{{19}}h\\
c.\\
t = \frac{{48}}{{95}}h
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a.\\
{v_{t/n}} = {v_{t/b}} - {v_{n/b}} = 6 - 3,5 = 2,5m/s\\
{t_{di}} = \frac{1}{{{v_{t/n}}}} = \frac{1}{{2,5}} = 0,4h\\
b.\\
{v_{t/n}}' = {v_{t/b}} + {v_{n/b}} = 6 + 3,5 = 9,5\\
{t_{ve}} = \frac{1}{{{v_{t/n}}'}} = \frac{1}{{9,5}} = \frac{2}{{19}}h\\
c.\\
t = {t_{di}} + {t_{ve}} = 0,4 + \frac{2}{{19}} = \frac{{48}}{{95}}h
\end{array}\)