FrictionFriction - - is a force that resists the

motion of objects on surfaces.

Jennifer Brown

What Causes Certain Kinds Of Friction?

Jennifer Brown

Jennifer Brown

Many kinds of friction exist. Can you name any?

› Sliding Friction

› Rolling Friction

› Air Friction

› Static Friction

› Viscous Friction

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Jennifer Brown

Jennifer Brown

Jennifer Brown

Friction depends on both surfaces in contact.

When the Hockey puck slides on ice, a thin layer of water between the rubber and the ice allows the puck to slide easily.

Jennifer Brown

Jennifer Brown

How do we identify various types of How do we identify various types of frictional forces?frictional forces?

Friction is a force, measured in newtons (N) just like any other force.

1) Static friction1) Static friction keeps an object at rest from moving.

Jennifer Brown

Jennifer Brown

2) Sliding 2) Sliding frictionfriction

is a force that resists the motion of an object moving across a surface.

Jennifer Brown

Jennifer Brown

How do you think friction even How do you think friction even occurs? What does it depend on?occurs? What does it depend on?

› Friction depends on a material’s properties such as roughness, how clean the surfaces are, and other factors.

› The greater the force squeezing two surfaces together, the greater the friction force.

Jennifer Brown

Jennifer Brown

What could we do in order to increase the frictional forces in this situation?

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Jennifer Brown

Jennifer Brown

Jennifer Brown

Unless a force is constantly applied, friction will slow all motion to a stop eventually.

Can we eliminate friction completely?

› No, only reduce it

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Jennifer Brown

2012 Maserati GranCabrio Sport2012 Maserati GranCabrio Sport

The friction that results from automobile parts rubbing together during car operation can be extremely great.

This is the reason why the oil in a car must constantly be changed and checked on a regular basis. This reduces the frictional forces.

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Jennifer Brown

Grooved tire treads allow space for water to be channeled away from the road-tire contact

point, allowing for more friction in wet conditions.

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Jennifer Brown

Shoes are designed to increase the friction between their soles and the ground.

Cleats

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Jennifer Brown

How else can friction be beneficial, or How else can friction be beneficial, or possibly harmful?possibly harmful?

Friction changes energy of motion into heat energy.

Jennifer Brown

Jennifer Brown