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14 Cards in this Set
- Front
- Back
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The ___ ____ states that sideward pressure exerted by a moving fluid decreases as the fluid's velocity increases.
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Bernoulli principle
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Why do balloons and airships float in the atmosphere?
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Because they are lighter than the air they displace.
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An ______ has a curved top surface and a flat bottom.
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airfoil
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How does the airfoil work as an airplane wing?
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The air travels higher over the curved top than it does on the flat bottom, causing the air to push the wing up.
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The difference in pressure of the upper and lower surface of the wing (airfoil) is called ___.
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lift
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Lift must over the force of ___ if a plane is to fly.
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gravity (weight)
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The force that drives a plane forward through the air, allowing the wings to create life, is called ________.
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thrust
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Most airplanes use ______ to create thrust.
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jet engines
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____ is the force exertd by the air that tends to slow the movement of a plane.
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Drag
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Drag is caused by _____ with the plane's surface, the inertia of the air and the pressure difference in front and behind the plant.
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friction
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What are some ways drag can be reduced?
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1. design planes with smooth surfaces and shapes
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The science of shaping objects so they allow the easy flow of fluids to reduce drag is called _____.
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streamlining
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Name some machines that streamlining is important to:
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1. airplans
2. trains 3. cars |
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Why do golf balls with dimpled surfaces travel farther?
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The dimples cause the air to fill the "holes" in the air behind the ball faster, reducing drag and allowing the ball to travel farther.
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