Đáp án:
\(\begin{array}{l}
a.\\
{v_{xe}} = \frac{{m{v_0}}}{M}\\
b.\\
{v_{xe}} = \frac{{m{v_0}}}{{M - m}}
\end{array}\)
Giải thích các bước giải:
\(\begin{array}{l}
a.\\
{v_0} = {v_{vat}}\\
{p_{vat}} = {p_{xe}}\\
m{v_{vat}} = M{v_{xe}}\\
{v_{xe}} = \frac{{m{v_{vat}}}}{M} = \frac{{m{v_0}}}{M}\\
b.\\
{v_0} = {v_{vat}} - {v_{xe}}\\
\Rightarrow {v_{vat}} = {v_0} + {v_{xe}}\\
{p_{vat}} = {p_{xe}}\\
m{v_{vat}} = M{v_{xe}}\\
m({v_0} + {v_{xe}}) = M{v_{xe}}\\
\Rightarrow {v_{xe}} = \frac{{m{v_0}}}{{M - m}}
\end{array}\)