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friction

FRICTIONBy:-Akshat Trivedi11th-A

ObjectivesExplain why friction occurs.List the two types of friction, and give examples of each type.Explain how friction can be both harmful and helpful.

What is friction?Is a force that opposes motion between two surfaces that are in contact

When does friction occur?Friction occurs when two surfaces are in contact

Friction enables a car to move on road without skiddingIt is because of the friction between the tyres of car and the road which enables car to move forward without skidding.

If there were no friction , car would stay where it was.

Why does friction occur?Because the hills and valleys of a surface are in contact with the hills and valleys of other surfaces, this produce friction.

What is Friction ?

Friction (frictional force) is a force that acts in a opposite direction to movement.

The force which always opposes the motion of one object over another, object in contact with it , is called friction.

Friction Enables Us to Write and Draw on PaperIt is because of the friction between the tip of the pencil ( or pen) and paper.Carbon particles from the pencil lead rubs off from it, due to the friction, which appears as black marks on the paper.

Friction depends onRoughness of surfaces and Force that objects are being pressed one against the other; or their weights

What increases friction?Rough surfacesAnd weight of objects

What does the amount of surfaces depend on?the amount of friction depends on how well the surfaces grip each other.Tyres on a road have very high friction (they don't slip),skates on ice have very low friction (they slip easily).

In a liquid or a gasFor a solid object moving through a liquid or gas,the amount of friction depends on the shape and surface area of the objectand the viscosity (thickness or thinness) of the liquid.

Car move due to the friction

Friction enables a car to move on road without skiddingIt becomes sometimes difficult to drive and control car on wet road.This is because of water present on road reduces friction.

Friction Enables Us to Pick Up and Hold Things in Our HandsWe can hold a glass tumbler in our hands because of friction between the tumbler and our hands.Similarly, we can pick up the books laying on the desk by our hands.

Friction Enables us to Light a MatchstickFriction also produces heat.We rub matchstick against the rough side of a matchbox, then friction between both of them produces heat and this heat burns chemicals present at the head of matchstick and it lights up.

TYPES OF FRICTIONKINETIC ANDSTATIC

What is kinetic friction?Is the friction between two moving surfaces

Sliding and Rolling

Static frictionIt occurs when a force is applied to an object but this object doesnt move.

1.Friction enables us to walk without slippingIt is because of the friction between the sole of the shoe and ground prevents us from slipping.

While walking , we push the ground backwards and the force of friction acts in the opposite direction (i.e. in the forward direction) and prevents us from slipping. By making the balance.

Disadvantages of FrictionSoil erosion caused by wind (friction of a fluid).Holes in your shoes, jeans. (friction of a solid) high frictionLack of friction is dangerous too, you may fall if the floor is very slippy.

1.Friction Wears Away the soles of Our ShoesWhen we walk on the road, tiny surfaces of the shoe keep on breaking off slowly due to which the soles of our shoes wear out slowlyDue to which shoes get damaged and becomes unfit to wear.

2.Tyres of Vehicles Wear out Gradually Due to FrictionLike the shoe tiny particles of tyres also breakdown due to friction when they run on road.The same thing also happens with the bicycles

Effect to Tyres Due to Friction

Before -After

4.Friction wears Out Steps Of Staircases in Building and Foot Over-BridgesThe friction between the soles of the shoes and wear away hard stone steps slowly.Such type of staircase are usually seen at :Railway stationOffices Old Buildings

5.Friction Slows Down MotionFriction reduces the motion of moving parts of a machine . In fact all the moving things such as (cars , buses, airplanes, boats, ships ,etc.) are slowed down by friction.

Some ways to reduce friction

Some ways to increase friction

Conclusion Friction is a necessary evilWe hate it sometimes but we also need it .It is very useful and but harmful too.