1. Wednesday, 9/30
We are taking notes today…take out your notebook/paper and something to write with.
In your notes respond to the following (3 minutes):
1. We have talked about velocity and its components (distance and time). Use your drawing skills to describe velocity without numbers.
2. We have talked about acceleration and its components (change in velocity and time). Use your drawing skills to describe acceleration.

2. Interpreting Motion Graphs

3. Two Types of Graphs
Position time graphs
Velocity time graphs

4. Position vs. time graphs
The slope of the graph is equal to the velocity
If the d/t graph is a straight line (no curve) then the velocity is constant.
Reference Point….

5. Position vs. time graphs
A line with a positive slope indicates positive velocity and the object is moving away from the reference point
A line with a negative slope indicates negative velocity and the object is moving towards the reference point.

6. Position vs. time graphs
If the line is horizontal (no slope) then the object is stationary (no velocity)

7. Position vs. time graphs Accelerated Motion
If the object is accelerating, the velocity is changing
p/t graph will no longer be a straight line, but will have a changing slope, resulting in a curve.
Doesn’t necessarily mean speeding up just changing.

8. Position vs. time graphs
Concave “Up like a cup”…the acceleration is positive
Does acceleration mean speeding up? No
Speeding up away
Slowing down towards

9. Position vs. time graphs
Concave “Down like a frown”…the acceleration is negative
Slowing down away
Speeding up towards

10. Velocity vs. time graphs
The slope is equal to the acceleration.

11. Velocity vs. time graphs
Positive velocity indicates the object is moving away from the reference point
The x axis means v=0
Green is slower, getting closer to zero.
Purple is speeding up, moving farther from the x axis.
Reference point is the sensor. X axis means your stopped. Can be stopped far away from the sensor or towards the sensor. Reference point is not X axis for velocity/time graphs.

12. Velocity vs. time graphs
Negative velocity indicates the object is moving toward the reference point.

13. Velocity vs. time graphs (Acceleration)
When the slope is zero:
horizontal line
velocity is constant
acceleration is zero

14. Velocity vs. time graphs
When the slope of the graph is positive:
the acceleration is positive

15. Velocity vs. time graphs
When the slope of the graph is negative:
the acceleration is negative

16. Velocity vs. time graphs
We cannot determine where an object’s position from a v/t graph, only its change in position.