1. Speed, Velocity and Acceleration
The Science of Speed
Speed, Velocity and Acceleration

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3. Speed Speed is a measure of how fast something is moving
Speed is a SCALAR quantity- it only requires a magnitude

4. Velocity The terms speed and velocity are used interchangeably
Velocity is speed in a given direction
Ex. A car travels 60 km/h north

5. Velocity is . . .
VECTOR quantity- it must have both magnitude and direction
magnitude is the speed of the object
direction: north, south, east, west, etc.

6. Comparison Speed is the magnitude of velocity
This means it is the number value associated with the velocity of an object

7. Average Speed
A quantity divided by time is a RATE

8. Average Speed
Does not indicate variations in speed of an object

9. Average Velocity
Occurs when either speed or direction changes
V =

10. Instantaneous Speed The speed of an object at any one instant
A football player does not always travel at the same speed

11. Speedometers measure the instantaneous speed of a car

12. Example 1
If the odometer reads zero at the beginning of a trip and 35 km a half hour later, what is the average speed? What is this speed in m/s?

13. Example 2
You travel 200 miles in 3 hours before stopping 30 minutes for lunch and gas. After lunch, you travel 150 miles in one and a half hours. What is your average speed?

14. Requires constant SPEED and DIRECTION
Constant Velocity
Requires constant SPEED and DIRECTION
The object does not speed up or slow down
The object moves in a straight line

15. Constant Velocity Graph
The velocity is equal to the slope of a distance versus time graph

16. Example 3
During her first track meet, Andrea runs with an average velocity of 6.02 m/s to the east. What distance does Andrea cover in 137 s?

17. Example 4
Last weekend I traveled from Lawrenceville to Dillard (100 km). If I drove 50 km/h for the first 50 km and 100 km/h for the second 50 km, what was my average velocity?

18. Position Time graphs Used to describe motion
Motion can be constant or changing
Motion can be in a positive or negative direction
Motion can be fast or slow
Slope of the line tells us the type of motion occurring

19. Slope of a Line

24. Three Little Pigs The wolf started from his house
The wolf traveled to the straw house.
The wolf stayed to blow it down and eat dinner.
The wolf traveled to the stick house.
Again he stayed, blew it down, and ate.
The wolf traveled to the brick house.
The wolf died in the stew pot at the brick house.