|If you shot a gun and dropped a bullet at the same time, how could they land at the same time? Wouldn't the acceleration behind the bullet keep it in the air longer?
If you shot the bullet horizontally, it really would hit the ground at the same time as the bullet you simply dropped. During the firing, the bullet would accelerate like crazy, but only horizontally. It would leave the gun with a velocity that was only in the horizontal direction. With no forces pushing on it horizontally after that (we'll neglect air resistance), the bullet will make steady progress downfield. But at the same time, it will begin to fall. The vertical component of its velocity will gradually increase in the downward direction as it falls. Like the dropped bullet, it will drift downward faster and faster and the two will hit the ground together.