Johns mass is 85.4 kg, and Barbars is 55.2 kg. He is standing on the x axis at xJ = +9.01 m, while she is standing on the x axis at xB = +4.65 m. They switch positions. How far and in which direction does their center of mass move as a result of the switch?

Answer 1

the distance between them is constant, but the cm will be closer to the larger mass

separation ... 9.01 - 4.65 = 4.36 m

cm ... 85.4 d = 55.2 (4.36 - d)
... d is the distance from John

when they switch, the cm will be closer to the origin
... because John will be closer to the origin