Friction Team Zeven

8/9/2019 Friction Team Zeven

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fRicTIoN


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08/30/12

NAME ER. NO. CLASSNikhil A. Gondalia 130390119034 ME-1

Pritendra . Matro!a 130390119028 ME-1

"a#an $. "anari%a 130390119109 ME-2

&ee' . (ani 140393119003 ME-2

M)"*MA+,AN+" ) ")&

G&E& +,5RAE,A NA,AR


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hat is Friction?

riction i6 a force 7eteen to 6rface6that are 6lidin: or tr%in: to 6lide acro66one another for e;a


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hat is Friction?

5he a


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hat is Friction?

riction al6o 'rodce6 heat. ore;a


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Useful Friction

and

Reducing Friction.

riction can 7e a 6efl force 7eca6e it

're#ent6 or 6hoe6 6li''in: on the'a#e


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Useful Friction

and

Reducing Friction.

ce ca6e6 #er% little friction hich i6 h%

it i6 ea6% to 6li' o#er on an ic% da%. t thi6i6 a :ood thin: for ice 6katin: and 6led:in:.


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Useful Friction

and

Reducing Friction.

"o


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When an object is in contact with a surface there is a force

acting on that object. The component of this force that isparallel to the surface is called thefriction force.

Friction Force

This resistiveforce is exertedon a movingobject due to

A!a"s o##osite tothe movement$$

viscosit" or othert"#es of frictiona

#ro#ert" of themedium in orsurface on !hichthe object moves.


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The force of friction

exerted by a surface to resist the motionof an object

friction is always parallel to the surfaceand acts in the opposite direction of theobjects attempted motion

the symbol isFf


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Friction: good or bad?

sometimes friction is aproblem: a skier puts wax on skis to reduce friction

between the skis and the snow

synoial fluid helps to reduce friction between themoing bones in joints of the human body

sometimes friction is necessary:

a car that is starting to moe re!uires friction

a person walking or running depends on friction


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Friction is the force acting oer the area ofcontact between two surfaces in the direction

opposite that of the motion. Types of friction forces

"tatic friction

#inetic friction

Friction


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When the two surfaces are not sliding across one anotherthe friction is called static friction.

"tatic Friction

5he re6i6ti#e forcee;ertedon the o7!ect ' to the ti


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#inetic or 'ynamic Friction

the force exerted on a moing object by asurface $Fk%

acts in the opposite direction of the

motion

if applied force is e!ual in magnitude tothe force of friction& the object will moe

with a constant elocity

if the applied force increases& the objectwill accelerate


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Types of #inetic Friction

sliding friction : an object is scraping orsliding across a surface

rolling friction : an object rolls across asurface

fluid friction or air resistance : an objecttraels through water or air andexperiences drag


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(oefficients of friction

is the ratio of the force of friction to thenormal force

symbol is the )reek letter mu $*%

*+Ff,FN

the coefficient of friction has no units or

direction since it is a ratio the coefficient of friction depends only on

the types of materials and can only be

determined experimentally


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for almost all situations the force re!uiredto start an object moing is greater thanthe force re!uired to keep it moing at aconstant elocity

so: Fsmax-Fk

since there are types of friction& there are different coefficients of friction for any

two surfaces coefficient of static friction $*s%

coefficient of kinetic friction $*#%


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"tatic riction

%N

fs

%

%g

The Force of Static

Friction keeps a

stationary object at

rest!

frictionstaticoftcoefficien

Ff

s

sNs

=

=


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inetic riction

%N

f&

%

%g

Once the Force of Static

Friction is overcome, the

Force of Kinetic Friction

is what slows down amoving object!

Motion

frictionkineticoftcoefficienFf

k

kNk

=

=


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"tatic friction opposes the impendingrelatie motion betweentwo objects.

is called the coefficient of kinetic friction.

#inetic Friction

#inetic friction opposes the relatie sliding motions that ishappening. The resistie force exerted on the object during itsmoement.

What is the direction of friction forces? opposite to the movement

/ormally much smaller than static friction00

kf =

0 1k

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