EVERYTHING falls at -9.8m/s if i remember my physics correctly. weather or not your arrow is shot up, down, left or right its still falling a the same rate. drop an arrow and a 20lb weight. i betcha they hit the ground at the same time. if you drop and arrow and shoot and arrow at the same time, from the same exzact height, on a perfectly level plane they will both hit the ground at exzactly the same time...just the way physics works....heck...shot a bullet at the same time as your arrow and its STILL going to hit the ground at the same exzact time as your arrow...itll just be farther away because its traveling faster...