import java.awt.Graphics; import java.util.ArrayList; public class Balls { double x = 100; double y = 10; double dx = 10; double dy = 0; double dt = 0.2; double u = 0.9; double g = 15; public void move(int height, int width) { if (y == height - 30) { dx *= u; } if (y > height - 30) { y = height - 30; dy *= u; dy = -dy; } else { dy += dt * g; y += dy * dt + 0.5 * g * dt * dt; } if (x > width - 30) { x = width - 30; dx = -dx; } else if (x < 0) { x = 0; dx = -dx; } else { x += dx; } } public void draw(Graphics g) { g.fillOval((int) x, (int) y, 30, 30); } }