일반물리학 1 — Center of Mass and Linear Momentum: Problem 66

66 Block 1, with mass $m_1$ and speed $3.0 \text{ m/s}$, slides along an $x$ axis on a frictionless floor and then undergoes a one-dimensional elastic collision with stationary block 2, with mass $m_2 = 0.40 m_1$. The two blocks then slide into a region where the coefficient of kinetic friction is $0.50$; there they stop. How far into that region do (a) block 1 and (b) block 2 slide?