Chapter 12 Section 1 Part 2

Velocity Velocity is the speed of an object in a particular direction. Example: an airplane’s velocity is 600 km/hr south Velocity changes when an object’s speed or direction changes.

Practice Which of the following are examples of velocity? A. 25 m/s forward B. 1,500 km/h C. 55 m/h south D. 33 m/h Answer: A & C

Acceleration Acceleration tells you how fast velocity changes. Acceleration occurs when an object: 1. Speeds up 2. Slows down 3. Changes direction

Acceleration Continued Positive acceleration = velocity increases Negative acceleration = velocity decreases Acceleration = final velocity - initial velocity final time - initial time Example While riding your bicycle you go from a speed of 0 m/s to a speed of 5 m/s in 5 seconds. What is your acceleration? vf - vi = 5 m/s - 0 m/s = 1 m/s/s tf - ti 5s

Circular Motion An object traveling in a circle is always changing its direction so acceleration is occurring. Centripetal acceleration is the acceleration that occurs in a circular motion.

Acceleration on a Graph Acceleration on a graph is velocity vs time.