This is a written explanation of the basic principles of air resistance, or "drag". Drag is the force applied by a gas in opposition to an object's motion through said gas. Air resistance was first observed by Galileo Galilee, when, in 1590, he dropped several spheres of equal sizes and shapes but different densities off of the leaning tower of Pisa, in Italy. Previous to his experiments, it was commonly believed that objects fell at speeds proportional to their weights. This was disproved when Galileo observed that two balls of equal size and shape but unequal mass, when dropped at the same time, would hit the ground at the same time. He also noticed that two objects of equal mass but unequal shapes would NOT hit the ground at the same time. In other words, he observed that an objects speed through the air was dependent upon its shape, not it's weight. From this he concluded that there must be some force opposing them as they moved through the air - Air resistance.
Fluid Dynamics is the study of the laws governing fluids (non-solids). Aerodynamics is the physics of non-fluids (solids) moving through gaseous fluids. Finally, Air resistance falls within Aerodynamics as being the specific study of the forces opposing an objects motion through a gas. In the terms of the field, air resistance is referred to as "Drag". That is the term I will be using throughout this paper.
Generally speaking, there are two types of drag - Friction Drag and Form Drag - there is a third type however, Induced Drag, that only affects airplanes. In this paper my primary focus will be Friction drag, my secondary will be Form drag, and my tertiary will be Induced drag, which I will mention only in passing.
o Friction Drag is the friction produced as an object moves through the air. It occurs next to the surface of an object. As the object moves through the air a thin layer of air forms around the surface of the object; this is known as the Boundary Layer.
