A pilot releases a package from a plane flying horizontally at a constant speed. When the package reaches the ground below, what is the horizontal location of the plane with respect to the package? Assume air resistance is negligible.

(A) The plane will be located behind the package.

(B) The location of the plane with respect to the package will depend on the initial height of the plane when the package was released.

(C) The plane will be located ahead of the package.

(D) The plane will be located directly above the package.

(D) The plane will be located directly above the package.

Explanation:

The plane is traveling at constant speed, we can assume that its path is a straight line. The plane has a certain horizontal speed, the package initially is inside the plane thus it is traveling at the same horizontal speed as the plane. At the time of the drop, both plane and package have the exact horizontal speed, this means that regardless of the the height of the drop or the vertical speed acquired by the package, both plane and package will cover the same horizontal distance during the fall of the package. This can only mean that the package is located directly below the plane at the moment the package hits the ground.

At WWII, planes that dropped bombs had to take this into consideration and in order to hit a target they would have to drop the bombs at some horizontal distance away from the target.