Friction

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Friction
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What is the Net Force?
ZERO!
THERE IS NO ACCELERATION
50 lbs
Velocity 2 mi/hr
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What direction does the FORCE of FRICTION act?
Weight
FRICTION
Normal Force
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Normal Force
Force of Friction µ Normal Force
Ff µ FN
µ is the coefficient of friction!
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Coefficient of Friction
Force of Friction
Normal Force
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Ff µ FN
http//www.drivingcamp.it/FOTO/Neve02.jpg
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Ff µ FN
Increases the Friction Force!
Increase Normal Force
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Ff µ FN
Increase µ
Increases Ff
http//www.alpinelimo.com/tire.jpg
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Ff µ FN
Decrease Normal Force
Decreases Force of Friction!!!
http//www.jmevans.fsnet.co.uk/DriveChallenge/Skid
_car.jpg
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Ff µ FN
Decrease Force of Friction!!!
Decrease µ
http//www.imoc.co.uk/news/img/skid-10.jpg
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Ff µ FN
How can a climber just stand there like that
without using their arms?
http//users.bigpond.net.au/pb/Sonja.jpg
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FN
The normal force FN is always perpendicular to
the surface it acts on!
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Fx
FN
Fy
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Dynamics of Friction
Kinetic Friction
Static Friction
Break Free of Static Friction
Force of Friction
Pull on String
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µstatic gt µkinetic
Pull
Friction
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A.B.S?
http//mirrorimageorigin.collegepublisher.com/medi
a/paper299/stills/91lgzfkc.jpeg
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http//www.yorkvillagefire.com/mva121203b.jpg
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Fluid Friction
"Air Resistance"
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http//www.ecy.wa.gov/programs/air/images/Emisch1.
jpg
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Air Resistance is a function of Cross Sectional
Surface Area and Velocity
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http//superunleaded.org/img/freeway.jpg
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What is TERMINAL VELOCITY?
Net Force ZERO
Acceleration ZERO
Velocity is CONSTANT
TERMINAL VELOCITY