Q 11-05-030NEETJEE MainEAMCET 2009 (Engineering)Medium
A body of mass $5$ kg makes an elastic collision with another body at rest and continues to move in the original direction after the collision with a velocity equal to $\dfrac{1}{10}$ of its original velocity. The mass of the second body is
Answer: (A) $4.09$ kg
Concept. Elastic, target at rest: $v_1 = \dfrac{m_1 - m_2}{m_1 + m_2}u$.
Step 1. Equation. $\dfrac{5 - m_2}{5 + m_2} = \dfrac{1}{10}$.
Step 2. Solve. $m_2 = \dfrac{45}{11} \approx 4.09$ kg.
Answer. $4.09$ kg (Option A).
Solution by Sreeraj P, M.Sc Physics