FRICTIONBy:-Akshat Trivedi

11th-A

Advantages and Disadvantages of Friction

220/02/2014

Objectives… Explain 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 skidding

It 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 Paper It 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 on…

Roughness of surfaces and

Force that objects are being pressed one against the other; or their weights

What increases friction?

Rough surfaces And 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 gas For 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 skidding

It 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 Hands We 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 Matchstick

Friction 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 FRICTION KINETIC AND STATIC

What is kinetic friction?

Is the friction between two moving surfaces

Sliding and Rolling

Static friction It occurs when a force is applied to an object but this object doesn’t move.

1.Friction enables us to walk without

slipping It 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 Friction

Soil erosion caused by wind (friction of a fluid).

Holes in your shoes, jeans. (friction of a solid) high friction

Lack of friction is dangerous too, you may fall if the floor is very slippy.

1.Friction Wears Away the soles of Our Shoes

When 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 slowly

Due to which shoes get damaged and becomes unfit to wear.

2.Tyres of Vehicles Wear out Gradually Due to

Friction Like 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

3.Friction wears Out the Brake Pads of Vehicles

Gradually Brake pad is made of rubber When the brakes of the vehicles are

applied a lot of friction is produced Friction wears out the brake pads

gradually

Before - After

4.Friction wears Out Steps Of Staircases in

Building and Foot Over-Bridges

The friction between the soles of the shoes and wear away hard stone steps slowly.

Such type of staircase are usually seen at :

Railway station Offices Old Buildings

5.Friction Slows Down Motion

Friction 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 evil We hate it sometimes but we also need

it . It is very useful and but harmful too.

Advantages and Disadvantages of Friction

3120/02/2014

Advantages and Disadvantages of Friction

3220/02/2014