1. Speed
Pages 220 – 223

2. Speed (v)
Speed, v, is the distance an object moves in a certain length of time
It is a scalar quantity meaning it has only magnitude (size) and is represented by a number and units
The most common units for speed are m/s and km/h

3. Graphically Speed is found by the slope of a distance-time graph
Remember that slope is found by the formula

4. Average vs. Instantaneous
As an object moves, it often undergoes changes in speed. Therefore, we sometimes use different terms to describe speed of an object during movement.
Average Speed (vave) is the total distance an object travels divided by the time it takes to travel that distance

5. Instantaneous Speed (vinst) is the speed of an object at a specific instant in time
It is found by the distance of the object at that instant divided by the time
Can you think of a real life example of average vs. instantaneous speed?

6. Constant & Changing Speed
Constant speed occurs when an object travels the same distance for each time interval
Changing speed occurs when an object travels a different distance for each time interval

8. Velocity
Pages 228 – 230

9. Velocity
Velocity describes the change in an objects position over time
It is a vector quantity meaning it describes magnitude (size) and direction and is represented with a number, units and a direction
The units for velocity are the same as those seen with speed: km/h and m/s

10. Graphically
The slope of a position-time graph is velocity

11. Average vs. Instantaneous
Average velocity is the displacement of an object divided by the time interval it takes to travel that displacement

12. Instantaneous velocity is the velocity of an object at a specific instant in time.
It is found by the position of the object at that instant divided by the time

13. Constant & Changing Velocity
Constant velocity occurs when an object travels the same speed and same direction for each time interval
Changing velocity occurs when an object’s speed or direction, or both speed and direction change for each time interval

14. Practice Problems Page 227 #’s 4, 5abc, 10, 11, 13, 14