A blue and a green billiard ball, each with a mass of 0.15 kg, collide directly. Before the collision, the blue ball had a speed of 3 m/s while the green ball had a speed of 2 m/s. After the collision, the blue ball stays in place while the green ball continues in motion. In 3-4 sentences, represent the situation before and after the collision and calculate the speed of the green ball after the collision. Be sure to discuss direction.