# Paper Airplanes

## Transcription

Paper Airplanes
```Paper Airplanes
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Rachael Lee (15)
Why?
• Why are the airplanes able to fly after
the initial thrust we gave them?
• How are they able to glide for so long
afterwards?
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Well, …
• Many different paper airplane designs
• --> Affects physics applied to it
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QuickTime™ and a
decompressor
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QuickTime™ and a
decompressor
are needed to see this picture.
QuickTime™ and a
decompressor
are needed to see this picture.
Factors:
•
•
•
•
•
Lift
Air Drag (or Air Resistance)
Density
Pressure
Thrust
Lift
• Your paper airplane uses lift to carry it
through the air and to its landing area.
• How?
• Lift can only happen when in the
presence of a moving fluid
• --> air has fluid properties.
Simulate it!
• This can be easily simulated in everday
life. Next time you are riding in a car
with someone stick your hand out the
window. Have your fingers pointing in
the direction of the motion of the
vehicle. Now move your hand up and
down slightly. You can feel the lift and
Equation
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L = lift
Cl = lift coefficient
(rho) = air density
V = air velocity
A = wing area
Air Drag
• resistive force of the air pushing back.
• limits flight distance
• Too high -> trying to throw a paper
airplane under water
• Equation:
Density
• the amount of mass compacted into an
area of an object
• Equation: p=m/V
• helps define the air resistance
• Temperature - also a factor of density
Pressure
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•
Like you might feel pressured to do homework
Equation: P=F/A (force ÷ area)
acts in all directions
acts on a paper airplane by exerting a force over
the airplane
• separate equation that relates pressure to the parts
of a fluid such as density, depth and gravitational
field strength
• P=pgh (P = pressure, p = density, g = gravitational
strength, h = depth)
• Means that higher you go in the air, the less
pressure there is.
http://ambitiontofly.files.wordpress.com/2011/10/wings_flow_air2.g
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Thrust
• long distance flight
• lift is dependant on thrust with an airplane
• If thrust = air resistance, then the object is
stationary
• cannot be maintained --> paper airplanes come
down
• related to Newton's first law: in the absence of an
external force, a body at rest remains at rest and a
body in motion remains in motion
• Use Newton’s second law: F=ma (force is equal to
the mass of an object multiplied by the
acceleration)
References
• http://www.123HelpMe.com/view.asp?id=153261
• http://paperplane.org/Aerodynamics/paero.htm
• http://blogs.bu.edu/biolocomotion/2011/10/21/thephysics-of-paper-planes/
```