Explanation: \(\text{Hints: } \text{ধাক্কা পূর্বে এবং পরে ভরের এবং গতিশক্তির সমতা।}\) \(\text{Solve: } m_1u_1 + m_2u_2 = m_1v_1 + m_2v_2 \implies mv + 2m(-v) = mv + 2mv_2\) \(\implies -v = v_1 + 2v_2 \implies v_1 - 2v_2 = -v \, \dots \, (i)\) \(\frac{1}{2}m_1u_1^2 + \frac{1}{2}m_2u_2^2 = \frac{1}{2}m_1v_1^2 + \frac{1}{2}m_2v_2^2\) \(\implies mv^2 + 2m(-v)^2 = mv_1^2 + 2mv_2^2\) \(\implies 3v^2 = v_1^2 + 2v_2^2 \, \dots \, (ii)\) \((i) \text{ এবং } (ii) \text{ সমাধানে, } v_2 = \frac{v}{3}, v_1 = -\frac{5v}{3}\) \(\text{Ans. (B)}\)