1. Chapter 10-2
Friction and Gravity

2. Friction Force of Friction – caused by two surfaces rubbing
Strength: depends on
1) how hard the surfaces are pushed together
2) types of surfaces
Direction: Opposite to direction of motion

3. Types of Friction
Static Friction – friction that acts when an object is not moving.
Need to overcome to START moving
Sliding Friction – friction that acts when an object is moving
Less than Static Friction
Sliding
Sliding Friction

4. Types of Friction
Rolling Friction– friction that acts when an object rolls
Less than Static Friction or Sliding Friction
Fluid Friction – friction that acts between a solid and fluid(remember a gas is a fluid)
Less than Static or Sliding