Two identical point charges (q = +7.60 x 10-6 C) are fixed at diagonally opposite corners of a square with sides of length 0.470 m. A test charge (q0 = -2.20 x 10-8 C), with a mass of 7.20 x 10-8 kg, is released from rest at one of the empty corners of the square. Determine the speed of the test charge when it reaches the center of the square.