Chapter 10-3 Warm-Up 1. What are three factors that can change an object’s acceleration? 2. What units are used to measure speed? Acceleration? 3. What is the equation for acceleration? 4. What is happening in the graph (red line)?

Chapter 10 - 3 Motion and Force

Force Force – a push or pull Net force – a combination of all forces

Force Force Latin word “fortis” which means strength Example - fortress

Forces Balanced Forces – Equal forces acting in the opposite direction A. No movement occurs Unbalanced Forces – Unequal forces acting in any direction A. Movement occurs

Friction Friction - A force that opposes motion between two surfaces that are in contact “Hills and valley”

Static Friction Static Friction – The force that resists the initiation of sliding motion between two surfaces that are in contact and at rest. A. Requires the most amount of force

Kinetic friction Kinetic Friction – The force that opposes the movement of two surfaces that are in contact and are sliding over each other.

Types of Friction Sliding Friction – Objects slide past each other

Types of Friction Rolling Friction – Object rolls over a surface

Types of Friction Fluid Friction - Object moves over a liquid or gas Streamlining

Friction Harmful Friction – Reduce the amount of friction A. Lubricant – Substances that reduce friction (oil, wax, grease)

Friction Helpful Friction – Need this friction to function Sand on ice, tires on cars, feet and the ground Hydroplaning