Two particles X and Y, of equal masses and with unequal positive charges, are free to move and are initially far away from each other. With Y at rest, X begins to move towards it with initial velocity u. After a long time, finally:

Answer

A

Explanation

Equal electrostatic force (mutual interaction) acts on X and Y but in opposite direction which accelerate Y but retards X. After long time the velocity of X becomes zero while Y becomes u.