Two concave mirrors of equal radii of curvature R are fixed on a stand facing opposite directions. The whole system has a mass m and is kept on a frictionless horizontal table (see fig). Two blocks A and B each of mass m are placed on the two sides of the stand. At t = 0 the separation between A and the mirror is 2R and also the separation between B and the mirror is 2R. The block B moves towards the mirror at a speed v. All collision which take place are elastic. Taking the original position of the mirror-stand system to be x = 0 and x-axis along AB.

(i) The position of image of A and B at t = -