Friction

Let's watch the video below to at least understand the concept of friction before lesson starts. Enjoy ;)

Friction is a force that opposes the movement of an object which it can occur when two surfaces are in contact with each other. Hence, friction is known as a type of force.Friction slows down the movement of an object.

A marble moves faster on glass surface (Smooth surface)

A marble moves slower on rough surface (sand paper)

There are some effects of friction such as :

1) makes the surfaces warm, 

2) makes it hard to move a heavy object,

3) causes wear and tear of surfaces of objects,

4) makes a moving object slow down and stop, 

5) enable an object to stay in a stationary position. 

The causes of friction are depending on : 

1) condition of surface- a smooth surface produces a smaller friction, while a rough surface produces a    greater friction,

2) the weight of object- a heavier object produces a greater frictional force.

Benefits of friction :

1) allows us to walk or run without slippping

2) allows a moving vehicles to slow down or stop

3)enables us to hold things, 

4) enables us to sharpen a knife.

Drawbacks of friction :

Friction cause tyres to wear out

1) causes the soles of tyres and shoes to wear out

2) produces heat in machines

3) causes wasting  of energy

Methods to reduce friction :

1) using rollers or ball bearings,

Ball bearing and oil can reduce friction

2) using lubricants such as oil, wax or grease,

3) smoothening the surfaces.

4) using an aerodynamic shape.