a circular of radius R with uniformly distributed positive charge Q on its circumference is located in xy plane with its center at origin O . a particles of mass m and charge q is at origin . it is slightly disturbed towards +z axis . kinetic energy when it reaches at z= R*root 3.
Three charges each of value Q are placed at points A(-K,0) ,O(0,0) and B(0,K).if force on point charge at A is ai + bj then force on point charge at B is