Box Dive

A cylindrical water tank is filled with some water, and its floor area is 0.02m². A cube whose side is 10cm long is suspended so that its bottom is 1.00m over the water surface, and its density is 2/3 that of water. Now the cube is gently released and drops into the water. Find the distance (in centimeters) the cube travels until it starts moving upwards for the first time .

Note: Ignore any resistance between the cube, air and water. Assume that the water behaves perfectly smoothly and does not disturb the cube's movement so that the cube always moves in a straight line. The tank is tall enough so the cube never reaches the tank floor.