Twoparticlesofequalmassesm$1=$m$2$moveonafrictionlesshorizontalsurfaceinthevicinity

$2$k$/$m$1.$ ofafixedforcecenter,withpotentialenergiesU $=1$kr$2$andU $=1$kr$2.$Inaddition,theyinteractwith

$121222$

each other via a potential energy U $=1$ kr$2,$ where r is the distance between them and and k are