Note: In all cases the paper should rise and the ball should "fly" in the stream of air. The movement of air over the curved surface of the paper (airfoil) creates a low pressure area above the "wing" and allows the higher pressure air below the paper to "lift" it. Bernoulli�s principle states that a fluid-like air exerts less pressure when it is moving quickly than when it is moving slowly. (Actually, an increase in the velocity of a fluid is always accompanied by a decrease in the pressure exerted by that fluid.) The lift created by the movement of air over a wing must be enough to support the weight of a plane and its contents for the plane to fly.
Another force acting against a plane is drag. Drag is created by the resistance of the air to the movement of a plane through the air. Usually, the sleeker the design, the less drag is created. The force used to counteract drag is thrust. Thrust is created by the motor or engine in a powered plane.
Page Last Modified: 03/27/08 18:41 EDT
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