## Essential University Physics: Volume 1 (4th Edition)

$-4.6m$
The initial and final centers of mass must be equal. Thus, it follows: $\frac{m_Jx_{Ji}}{M}= \frac{m_J \times(x_{Ji} + 19 + x_{cf})+m_cx_{cf}}{M}$ We simplify to find: $x_{cf} = \frac{-19m_J}{m_J+m_c}$ Plugging in 4.8 for $m_J$ and 15 for $m_c$, it follows: $x_{cf}=-4.6\ m$