So the soccer ball hits the crossbar (assuming it hits at 2.5 meters high). What does that mean? Do what fss said and break the motion into components, x and y. 2.5 is the positive y displacement. So we have 2.5 = vy (t) + 1/2a(t^2). So what is vy? and what is a? If you have a question about that, add a reply. So you should solve for t, using the quadratic formula. Then, in the x direction, you have distance (in the x-direction of course) = vx (t). So once you get t, you can plug in so you find the distance it traveled in the x-direction.