Friction

1
Friction

• An opposing force that effects us everyday

2
First, remember what a force is!!

• Force push or a pull on an object

3 Characteristics
1. Have size
2. Have direction
3. Have units
3
What is Friction Then?

• Friction a force that opposes motion between two
  surfaces that are touching

There is NO SUCH THING as a completely smooth
surface!!
4
The Source of Friction

• The surface of any object

Hills and Valleys
There are microscopic hills and valleys on the
surface of every object
As the surfaces move back and forth, the hills
and valleys stick to one another
5
What Controls The Amount of Friction?

• 2 Major Factors

1. Roughness of surfaces

• Rougher the surface more friction

2. Force pushing the objects together

• Greater the force more friction

6
2 Types of Friction

• Sliding Friction

Requires a great amount of force to move the
object
Large amount of opposing force
7
2 Types of Friction

• Rolling Friction

Requires much less force to move the object
Small amount of opposing force
8
How Can We Increase and Decrease Friction?

• Decrease Friction

Lubricants substances that are applied to
surfaces to reduce friction between them
Such things as Oils, Waxes, and Greases
9
How Can We Increase and Decrease Friction?

• Increase Friction

1. Increase the force acting on the object
2. Increase the roughness of the surface
Paperweights, Sand on roads, sanding surfaces