Friction

What is friction?

Friction is a force, affects motion. Friction acts on materials in contact with another, or acts in different direction in opposite motion.

What does the force of friction depend on?

• Kinds of materials in contact
• How much surfaces pressed together

..such as Rubber vs. Concrete, and not Steel vs. Steel (Rubber vs. Concrete > Steel vs. Steel)

Static Friction

• Opposes movement of stationary object
• Moving furniture
• Hardest part getting moving

Kinetic Friction

• Acts on objects in motion
• Once object begins moving, less force to keep in motion
• Sliding, Rolling, Fluid

Sliding Friction

Basketball shoes prevent slipping, relation to Sliding Friction

• Two objects slide past one another
• Basketball shoes prevent slipping

Rolling Friction

• Objects such as wheel or ball rolls across surface
• Easier to overcome than sliding friction

Fluid Friction

Boy with a helmet, on training wheels, relation to Fluid Friction

• Solid objects move through fluids
• Cyclists use aerodynamic and spandex to reduce friction

Air Resistance

• Friction acting on something moving through air
• Don't notice unless at high speed.