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?
- Nature of the materials.
- How hard the surfaces are pressed together
..such as Rubber vs. Concrete, and not Steel vs. Steel (Rubber vs. Concrete > Steel vs. Steel)
Static Friction :
Friction between the surfaces in contact and which are relatively at rest.
- Opposes movement of stationary object
- Moving furniture
- Hardest part getting moving
- Acts on objects in motion
- Once object begins moving, less force to keep in motion
- Sliding, Rolling, Fluid
- Two objects slide past one another
- Basketball shoes prevent slipping
- Objects such as wheel or ball rolls across surface
- Easier to overcome than sliding friction
- Rolling friction is always less than static friction.Because time period for contact of irregularities betwwen the bodies is less in rolling friction compared to static friction.
- Solid objects move through fluids
- Cyclists use aerodynamic and spandex to reduce friction
- Vehicles such as aeroplanes and cars have a special shape known as streamlined shape to reduce windshear or drag.
- Friction acting on something moving through air
- Don't notice unless at high speed.