Answer
Line segment 5 corresponds to the motion of the center of mass after the collision.
Work Step by Step
Line segment 1 and line segment 3 correspond to the positions of the two bodies before the collision. Line segment 2 corresponds to the motion of the center of mass before the collision.
Since the motion of the center of mass does not change during a collision, line segment 5 corresponds to the motion of the center of mass after the collision.
