1. Chapter 12 Section 1
Part 2

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.

3. 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

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

5. 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 s

6. 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.

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