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FRICTION By :-  L eena FRICTION By :-  L eena

FRICTION By :- L eena - PowerPoint Presentation

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FRICTION By :- L eena - PPT Presentation

gawas Sonam gosavi Neekita Bhowar FRICTION Friction is the force resisting the relative motion of solid surfaces fluid layers and material elements sliding against each other ID: 783480

surfaces friction force surface friction surfaces surface force object increases rolling move measuring sliding hairy fluid frictional motion coefficient

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Presentation Transcript

Slide1

FRICTION

By :-

L

eena

gawas

Sonam

gosavi

Neekita

Bhowar

Slide2

FRICTION

Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.

Slide3

Types of friction

Dry friction

:- is a force that opposes the relative lateral motion of two solid surfaces in contact. It is subdivided into

static friction ("

stiction"):- between non-moving surfaces. It exists between a stationary object and the surface on which it's resting.

Slide4

2) kinetic friction

:- between moving surfaces.

Also called as sliding friction

.

Eg. Rubbing both hands together to create heat

Slide5

Fluid friction :- describes the friction between layers of a viscous fluid. Also called as viscosity.

Rolling friction:-

is a force that slows down the motion of a rolling object.

B

all or wheel has rolling friction when rolled on a surface.

Slide6

Factors affecting friction

Types of surfaces

How hard the surfaces are pushed together

Mass of object

F=µN (N=mg)

Slide7

Friction increases when the force between two objects is

increased

.

What increases

Friction

Slide8

What increases friction

Rough surfaces

A pair of

rough surfaces

will have more

friction

than a pair of smooth

surfaces

, because the “peaks” of one

surface

can fall into the “valleys” of the other.

Weight of an object

Force friction= weight x coefficient of friction

So as the weight increases so does the amount of friction.

Slide9

Friction increases when surface area of an objects increases

Slide10

To reduce the amount of friction, apply a

lubricant

between two surfaces.

Motor oil,

wax, and grease are examples.Friction can also be reduced by rolling, rather than pushing, an object.

What decreases

Friction

Slide11

Slide12

Measuring Friction

M

easuring

friction have been investigated for more than 2500

years.

Amonton's

law was

originally

published

by

Da

Vinci and

later

rediscovered by

Amonton

.

Amonton's

law

states that

the

friction depends only on the force normal to the contact plane. From this, the friction

coefficient

can be defined as:

μ=

F / N

where

F is the force required to move an object on a horizontal surface and N is the load normal

to the surface.

Slide13

Friction Measuring Equipment

T2GO Portable Continuous Friction Measuring Equipment, CFME 

T2GO, which can measure friction on any surface both dry and contaminated. It is ideal for measuring in areas where it might be difficult to get access to with a larger trailer or vehicle type friction tester.

Slide14

A

n essential tool in the operation of traffic infrastructure during winter conditions.

This serves as a guidance to initiate remedying actions such as snow removal, distribution of de-icing chemicals and speed reduction, in order to enable a safe use of the traffic infrastructure.

Slide15

Friction in plants

The stability of twining vines under gravitational loads suggests an important role for friction.

The coefficient of friction, μ, between vine stems and wood is high, often five times greater than between leather and wood.

Slide16

An interesting difference in frictional properties was the upright hairy segments had larger frictional interactions than the inverted hairy segments.

Slide17

FRICTION IN ANIMALS

Many animals have the natural ability to move on vertical walls and ceilings.

They attach to surfaces using claws, soft and hairy pads.

Recent studies have indicated that the frictional forces generated by these structures not only control the movement of animals but also significantly increase the reliability of their attachment.

Slide18

Snakes use Sliding Friction as they slither along. They use branches and sticks to push and slide along the ground or in trees.

In fact their scales are perfectly designed to keep the snakes from sliding backwards or

sideways while

climbing

Slide19

Snails use fluid friction as they give out slime layer to protect their body from rough surface and improve movement.

It also acts as shield against parasites.

Slide20

Flies, geckos and beetles have ability to move on inclined surface using hairy pads.Soles of feet have elastic epidermis covered with setae which control friction and

genertes

opposite frictional forces.

Slide21

Snapping turtles great size makes it impossible for predators to prey on them unlike small turtles.

Static friction makes it harder for turtle to be moved by predator.

Slide22

The body of the mother-of-pearl moth caterpillar escapes predators by anchoring its tail, recoiling, and uses rolling friction for escape.

By turning into a wheel, the caterpillar moves some 40 times faster than its normal walking pace.

Slide23

Uses of friction

When surfaces in contact move relative to each other, the friction between the two surfaces converts

kinetic energy into thermal energy

(that is, it converts work to heat).

This property can have dramatic consequences, as illustrated by the use of friction created by rubbing pieces of wood or stones together to start a fire

Slide24

In space, meteors and comets have no force to slow them down. As they hit the Earth's atmosphere, however, not only does the atmosphere's friction slow them down, it tends to break them apart into smaller pieces, thereby lessening their impact on the Earth's surface.

Slide25

THANK YOU