Galileo's Law of Inertia states
that in the absence of all outside influences, an object's acceleration vector is zero.
(A vector is a numerical value which describes a specific amount of force and its
direction.) In other words, if there are no opposing forces to influence a moving
object, then it simply goes along its initial path! Now, using Galileo's
theory of inertia and what we know of the basic laws of aerodynamics,
we can assume that if we design a paper airplane that has balanced forces, that airplane
should remain in a constant and stable path.
Keeping that in mind, follow the instructions for the paper airplane
lab found in the right frame and see what happens!
Remember that for an airplane to fly, it must engage in a tug of war between opposing forces of lift versus weight and thrust versus drag