A bullet at 800 m/s horizontally hits a target that is 180m away. How far does the bullet fall before it hits the target?

The bullet falls 0.25m

The answer is -0.25m because it is falling, therefore it is negative.
Explanation:

t = dy/vy = 180m/800m/s = 0.23 secs

dy = 1/2 gt^2 = -0.25m

Gravity, from the center of mass of the box, extending downward normal force, from the floor under the box, extending upward, equal to gravity push force, acting at a point on the box, extending in the direction of motion friction, acting at any point on the box directly opposite the push, extending directly opposite to the motion