Two points, A and B, are located on the ground a certain distance $d=10\sqrt{2}m$ apart. Two rocks are launched simultaneously from points A and B with equal speeds but at different angles. Each rock lands at the launch point of the other. Knowing that one of the rocks is launched at an angle $\theta ={37}^0$ with the horizontal, what is the minimum distance between the rocks during the flight? (given $\cos {37}^0=4/5$ )