i like birds and since my avatar is a dragon i figured i would do the physics of flying especially considering i have absolutely no idea about what else to do and I have to do ten of these in the next two days :livid:. Moving on, there are three main forces that enable an object to achieve flight, being drag, lift, and thrust. To better understand flight we should consider air as acting like a fluid. It is not a liquid, like water, but is a called a fluid because the force needed to deform it depends on how fast it is deformed, not on how much it is deformed. Drag is a force exerted on an object moving through a fluid; it is always oriented in the direction of relative fluid flow. Drag occurs when the fluid, in this case air, and the object exchange momentum, creating a force opposing the motion of the object as we can see in the diagram. Drag is flights worst enemy!! Lift is another force exerted on an object moving through a fluid, generally directed upward as you probably know, opposing the weight of the animal that is pulling it down to earth. In animals, the angle of the wings against the flow of air creates a resistance that has the net effect of moving the wing upward. Thrust is the third and final force. Thrust is a force induced in the direction of the animal's flight, opposing the drag force. To fly at a steady speed in a completely horizontal direction, an animal must generate enough thrust to equal the drag forces on it. This is achieved by the animal flapping its wings vigorously. Fly birdie, fly!!