When I was rocking on a recliner at home I noticed the combined center of mass of me and the chair would move horizontally (also vertically).
The only apparent forces acting on this system is gravity and the normal force (on the chair), Bothboth of which cannot affect the motion of the center of mass horizontally. And the forces between me and the chair are internal.
How has the center of mass gone forward, what have I not factored in?
