Đáp án:
\(\begin{array}{l}
11.\\
a.\\
v = 0,6m/s\\
b.\\
v = 1,3m/s\\
12.\\
a.\\
{v_2} = \frac{{0,05.2 - 0,05{v_1}'}}{{0,08}}\\
b\\
{v_2} = 2,5m/s
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
11.\\
a.\\
p = p'\\
{m_1}{v_1} - {m_2}{v_2} = ({m_1} + {m_2})v\\
v = \frac{{{m_1}{v_1} - {m_2}{v_2}}}{{{m_1} + {m_2}}} = \frac{{38.1 - 2.7}}{{38 + 2}} = 0,6m/s\\
b.\\
p = p'\\
{m_1}{v_1} + {m_2}{v_2} = ({m_1} + {m_2})v\\
v = \frac{{{m_1}{v_1} + {m_2}{v_2}}}{{{m_1} + {m_2}}} = \frac{{38.1 + 2.7}}{{38 + 2}} = 1,3m/s\\
12.\\
a.\\
p = p'\\
{m_1}{v_1} - {m_2}{v_2} = {m_1}{v_1}'\\
{v_2} = \frac{{{m_1}{v_1} - {m_1}{v_1}'}}{{{m_2}}} = \frac{{0,05.2 - 0,05{v_1}'}}{{0,08}}\\
b.\\
p = p'\\
{m_1}{v_1} - {m_2}{v_2} = - {m_1}{v_1}'\\
{v_2} = \frac{{{m_1}{v_1} + {m_1}{v_1}'}}{{{m_2}}} = \frac{{0,05.2 + 0,05.2}}{{0,08}} = 2,5m/s
\end{array}\)
