Chapter 5.2 Frictionat the Sochi Winter Olympics

Frictionfriction is the force that opposes motion.

Causes of frictionSurfaces have tiny hills and valleys on both sides.

As the surfaces slide across each other the hills and valleys grind against each other.

Causes of frictionFriction depends on both surfaces.

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Types of FrictionStatic friction - friction force that resists motion between surfaces that are not moving.

Types of FrictionSliding friction - the friction force that resists the motion of an object moving across a surface.

Types of Frictionrolling friction - opposes motion of a rolling object.

Types of Frictionair friction - a force of the surrounding fluid (air) working against motion

Types of Friction

Types of FrictionMotion through water - viscous friction works much like air friction.

Effect of weight on frictionAdding weight to a sliding or rolling object adds friction between the two surfaces.

Which takes more force to push?

Decreasing Friction1. Lubrication - such as oil

2. ballbearings

3. Magnetic Levitation

Increasing Friction1. cleats

Increasing Friction2. Race tires vs Street Tires

- Street Tires increased friction in wet conditions.

- Race tires increased friction on dry roads.