Albert lets go of his balloon and the balloon starts rising vertically at a constant speed of 12 feet per second. Nora who is standing 18 feet from Albert is looking directly at the balloon, which was in her horizontal line of sight in the beginning, starts running toward the child at a constant speed of 5 feet per second. let y be the vertical distance between Albert and the balloon. a. express y as a function of t, time b. express x, the distance of Nora from Albert as a function of t.