1. Scalars and Vectors in Motion

2. Scalars vs. Vectors Scalars vs. Vectors
Scalar Quantity – physical quantity with
Magnitude
Example:
Temperature
Vector Quantity – physical quantity with
1) Magnitude (Size)
2) Direction
Example:
Force

3. Vector Sign Conventions+ Up
Down
Right
Left + _ + + _ _ _

4. Describing an Object’s Change in Position
How many ways can you get from point A to point B? A B

5. Distance vs. Displacement (d) (Δx)
The path-length of an object in motion

6. Displacement (Δx)– a vector that represents the change in position
Can displacement be negative?
Yes if xi > xf
Ex: moving left

7. Discuss the red devil’s motion (quantitatively) with a partner
Discuss the red devil’s motion (quantitatively) with a partner. Use the terms position, displacement, distance.
x (m)

8. Speed vs. Velocity (v) How fast an object is travelling
Ex: 6 m/s
How fast an object is travelling…
in a specific direction
Ex: 6 m/s downwards

9. If a buggy drove in reverse would it have a negative velocity?
5 m/s
Speed = 5 m/s
Velocity = +5 m/s
Speed = 5 m/s
Velocity = -5 m/s
5 m/s
If a buggy drove in reverse would it have a negative velocity?
Not if the buggy was reversing to the right/East!

10. Instantaneous and Average
Instantaneous speed/velocity is speed at a particular instant in time
Average speed/velocity is speed over whole journey

11. Calculating Average Speed and Velocity
When would these two quantities be the same value?
When would these two quantities be different?
Object moves in only 1 Direction
Object turns around

12. In Rio, Katie Ledecky broke her own world record in the 800-meter freestyle, finishing in 8 min 7 seconds. What was Katie’s average speed and velocity?

13. Getting a Feel for m/s Convert 1 m/s into miles per hour: >20 mph
So if you have a speed of 10 m/s, roughly how many mph is that?
Or if you are driving 65 mph, roughly how many m/s is that?
>20 mph
>32.5 mps