Friction New

Friction

MEANING ??

EFFECT OF FRICTION

WAY TO : ACTIVITY OF FRICTION FRICTION

REDUCE

ADVANTAGES

INCREASE DISADVANTAGES

MEANING ?? 1.

Friction is the force between two surfaces rubbing together.

2. Friction is the force between two surfaces rubbing together. It is high if the surfaces are dry and rough and it is low if the surfaces are smooth and wet.

Some friction activities Grass surface

More friction Heavy box

More friction

Floor surface

Less friction

lighter box

Less friction

Effect of Friction: 

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Palms becomes warm when they are rubbed together. The heat produced by friction causes these sparks. The tyres on your car are worn out and the road is wet and slippery, you will probably skid the car and have an accident. Shoes and the car's tyres need good grip so their surfaces are rough. This increases the friction between them and the ground. Friction produces noise and sound.

Here are some very simple facts: 1.

2.

3.

4.

When two smooth surfaces rub together there is very little friction. When two rough surfaces rub together there is more friction. There is less friction when there is a liquid (e.g. oil) between the two surfaces. There is more friction if the two surfaces are forced against each other.

Ways to reduce friction: 1.

Using rollers, marbles, wheels and ball bearing.

2. Put a layer grease, oil.

Ways to reduce friction: 3. Using air cushion.

4. Using aerodynamic shape.

1.

Ways to increase friction: Tread pattern on soles and tyres.

2.

Shoes with studs and spike give the wearer a better grip on the field.

3.

A cube of chalk is used to rub the tip of billiard or pool cue to increase friction with the cue ball.

Ways to increase friction: 4. Resin is applied on the bow of violin to increase friction between the string and the bow. 5. Rubber material have more friction than other materials. 6. Keeping surface dry.

Advantages of friction. 1. 2. 3. 4. 5. 6. 7.

We can walking and running. We driving a car. An object can stay stationary. Lighting a match. We can climbing. Fixing a nail. We can writing.

Disadvantages of friction. 1.

2. 3.

4.

Needs more effort to pull or push things across the floor. Causes tyres to wear out. Causes machines to slow down or stop moving. Causes machines to produce unwanted heat.