1616thth Oct Oct 09 09FrictionFriction

Learning ObjectivesLearning Objectives• To know what friction is.To know what friction is.• To learn some uses for friction.To learn some uses for friction.• Learn ways to reduce friction.Learn ways to reduce friction.

Keywords: FrictionKeywords: Friction

Starter

Name all the forces Name all the forces you can think of;you can think of;

forces

What is friction? What is friction? Think pair share!Think pair share!

Write a few examplesWrite a few examples

There is resistance to the rubbing motion. The name of this resistant force is FRICTIONFRICTION

Friction canFriction can;

Produce heat Peter

Wear things away Watts

Slow things down Spent

Make a noise Money

Rub your hands together for a minute. How does that feel?

What causes the heat?

Friction always tries to slow moving objects down. It opposes motionopposes motion.

It is a force between 2 touching objects.

Write down the numbers in your book for the missing words.

1. force 2. rough 3. smooth 4. surfaces

Friction is a ___________________ caused by two __________________ moving over each other. ___________________ surfaces produce more friction than __________________ surfaces.

Friction can be a friend or a enemy at times.

Bear did not read the warning sign

You can not hold a pencil in your hand without friction. The pencil lead would not make a mark on the paper without friction.

Writing

A pencil eraser uses friction to rub off mistakes written in pencil lead.

Your car would not start moving if it wasn't for the friction of the tyres against the street. With no friction, the tyres would just spin. Likewise, you could not stop without the friction of the brakes and the tyres.

Driving car

      

                                                                            

When objects rub against When objects rub against each other, the surfaces are each other, the surfaces are worn away. Friction with the worn away. Friction with the ground causes the heels ground causes the heels and soles of your shoes to and soles of your shoes to wear away.wear away.

Cars have a brake system that uses friction between the rear tyres and the brake pads to slow down or stop the car.

Friend Enemy

Multiple choice GameMultiple choice Game

What helps to reduce friction?What helps to reduce friction?Adding o-- and g-----, this is called Adding o-- and g-----, this is called

lubrication.lubrication.

reviewreview

A unit of force is:A unit of force is:

A A NewtonNewton

B B MetreMetre

C C GramGram

D D KilogramKilogram

Which example shows unhelpful Which example shows unhelpful friction?friction?

A A Friction between the tyre and the road.Friction between the tyre and the road.

B B Friction between the paper and the point Friction between the paper and the point of the pen.of the pen.

C C Friction in the wheel axles of the bicycle.Friction in the wheel axles of the bicycle.

D D Friction between your shoes and the floor.Friction between your shoes and the floor.

Which of the following about Which of the following about friction is incorrectfriction is incorrect

A A Friction slows down a ball rolling in grass. Friction slows down a ball rolling in grass.

BB Friction wears away tyres. Friction wears away tyres.

CC Friction can speed up a falling object.Friction can speed up a falling object.

D D Friction makes objects hotter.Friction makes objects hotter.

Which of these produce friction Which of these produce friction when they rub togetherwhen they rub together

A A A rough surface and a smooth one.A rough surface and a smooth one.

B B 2 smooth surfaces.2 smooth surfaces.

C C 2 rough surfaces.2 rough surfaces.

D D 2 smooth surfaces with oil between them.2 smooth surfaces with oil between them.

Whic of the following is not an Whic of the following is not an example of a lubricant?example of a lubricant?

A A Grease for bicycle chains. Grease for bicycle chains.

B B Rubber on car tyres.Rubber on car tyres.

C C Water on swimming pool tiles.Water on swimming pool tiles.

D D Oil in car engines.Oil in car engines.

A force is a A force is a

A A A spring.A spring.

B B A movement.A movement.

C C An engine.An engine.

D D A push or a pull.A push or a pull.

Friction is Friction is

A A A non contact Force.A non contact Force.

B B A magnetic force.A magnetic force.

CC A contact force. A contact force.

D D Uses static electricity.Uses static electricity.

What is the frictional force that slows What is the frictional force that slows something down through the air?something down through the air?

A A StreamliningStreamlining

B B GravityGravity

C C ThrustThrust

D D Air resistanceAir resistance

Learning OutcomesLearning OutcomesExplain what friction is.Explain what friction is.

State some useful applications for friction State some useful applications for friction in everyday life.in everyday life.

Name the ways to reduce friction.Name the ways to reduce friction.