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

$-46 \ m/s$
We know the following equation for elastic collisions: $v_{1f}=\frac{m_1-m_2}{m_1+m_2}v_{1i}+\frac{2m_2}{m_1+m_2}v_{2i}$ $v_{1f}=-v_{1i}+2v_{2i}$ $v_{1f}=-18+2(-14)=-46 \ m/s$