A stick of mass 6 kg lies on a smooth sheet of ice. A stone of mass 1.2 kg sliding along the ice at $8 \mathrm{~m} / \mathrm{sec}$ hits the stick perpendicularly at some point and rebounds at $2 \mathrm{~m} / \mathrm{sec}$. Describe the subsequent motion of the center of mass of the stick.