Question

A package falls from an airplane in level flight at constant speed. If air resistance can be neglected, how does the motion of the package look to the pilot

Answer 1

Answer: The package appears to fall straight downward

Explanation:

When the package is dropped from the plane (which has constant speed) it will follow a parabolic path. Then, as the plane and the package have the same constant speed in the horizontal component (X component of the movement) and a constant vertical acceleration due gravity, from the plane the package will always be seen below it, falling straight downward (free fall).

This is possible if it is assumed that there are no additional horizontal forces such as air resistance, thus fulfilling Newton's 1st Law of inertia that estates if a body is in equilibrium the sum of all the forces acting on it is equal to zero.