friction. what factors affect friction? types of surfaces how hard the surfaces are pushed together

FRICTION

WHAT FACTORS AFFECT FRICTION?

• Types of surfaces• How hard the surfaces are pushed together

TYPES OF SURFACES

• Smoother the surface- smaller the friction• Examples of smooth surfaces• ?• ?• ?

• The rougher the surface- greater the friction• Examples

WHAT HAPPENS WHEN WE CHANGE A SURFACE?

• How does adding rubber to the bottom of an object change the friction?

• What happens when the gym floor is dusty?• How are other ways a surface changes the

friction?

TYPES OF FRICTION

• Sliding• Two solid surfaces slide over each other• Direction of motion is OPPOSITE that of friction• Examples:

• Static• Objects that aren’t moving• Think about trying to push something that just won’t

move• examples

TYPES… CONT’D

• Rolling• When an object rolls across a surface• Easier to overcome than sliding friction• Think about pushing a bike, is it easier or harder if the

wheels are locked?

• Fluid• When a solid object moves through a fluid• Easier to overcome than sliding (think about an icy

sidewalk )

REAL LIFE EXAMPLES OF FRICTION

HOW HARD THE SURFACES ARE PUSHED TOGETHER………

• What does this really mean?

• What are real world examples of pushing surfaces together to increase friction?

HOW DOES FRICTION WORK?

WHAT IS FRICTION?• Friction is one of the most significant

phenomena in the physical world

• Surface resistance to relative motion; the rubbing of the surface of one body against that of another

• Leonardo Da Vinci (1452-1519) was one of the first scholars to study friction systematically.

WHAT IS FRICTION

• Force is so fundamental that it defies full explanation, and compared to force, friction is relatively easy to identify

• Friction plays a part in the total force that must be opposed in order for movement to take place in many situations

• Weight is another term for gravitational force and is an important factor in friction

FORCE TO DO FRICTION

• EQUATION

• F=μN=μmg

Where μ is the coefficient of friction (either static or kinetic), and N is the normal force. On a horizontal plane, the normal force is just the weight of the object, which is mg.

A POWERFUL FORCE• Friction can prove to be a very powerful force

even when dealing with small scale objects.• Ex: Phone Book Friction Video

FRICTION IN EVERYDAY LIFE• Driving a car: The force of friction encompasses

the entire operation of a car and makes the tires possible to turn on the road. Tires are designed with a degree of tread that helps maintain a high degree of friction to allow the tire to grip tightly to the road and keep control. If there was no tread, there would be no friction and the car would not be able to stop at the appropriate time.

FRICTION IN EVERYDAY LIFE

• Lighting a match: This has to do with friction because as you strike a match to be lit, friction creates enough heat to ignite a chemical compound in the match head that allows the rest of the match to continue to burn.

FRICTION IN EVERYDAY LIFE• Using your computer’s mouse pad: Friction occurs

between the mouse and the desktop or mouse pad. Friction is required to move the mouse and have it respond appropriately. If you were to use a different kind of material for a mouse pad, such as a piece of sand paper, the mouse is harder to move. The piece of sand paper has more friction than the mouse pad.

FRICTION IN EVERYDAY LIFE

• If we lived in a world with no friction, things may be a bit more chaotic. Automobiles, airplanes and other vehicles would have a tough time trying to slow down or stop because they would be trying to brake on a frictionless surface. This would be like trying to stop on an ice skating rink. There would be nothing to grip to the surface.

• Doing actions as simple as walking, writing, and eating would be impossible. Everything would be sliding around, never staying put. This could get very dangerous when we think about large bodies of water, or enormous structures not staying in place because we lived in a frictionless world.

• Gravity would become the defining force.

BIBLIOGRAPHY• http://dictionary.reference.com/browse/friction?s=t• http://www.scienceclarified.com/everyday/Real-Life-Chemistry

-Vol-3-Physics-Vol-1/Friction.html• http://www.scienceclarified.com/everyday/Real-Life-Chemistry

-Vol-3-Physics-Vol-1/Friction-Real-life-applications.html• http://www.articlesbase.com/k-12-education-articles/friction-fo

r-children-4-tricks-to-help-children-understand-friction-1416598.html

• http://www.nano-world.org/frictionmodule/content/0200makroreibung/0400historisch/0100leonardo/?=lang=en - Da Vinci

• http://www.school-for-champions.com/science/friction.htm - Friction Force

• http://www.youtube.com/watch?v=hOt-D_ee-JE - Video• http://ffden-2.phys.uaf.edu/211_fall2002.web.dir/

ben_townsend/staticandkineticfriction.htm - Car Image• http://en.wikipedia.org/wiki/File:Tire_tread.jpg - Tire Tread • http://jdaya15.wordpress.com/best-works/science-m/friction -

Match• http://www.cafepress.com/physfriction.31346452# - Mouse

Pad