1. Describing Motion with Diagrams

2. Describing Motion with Diagrams
Ticker Tape Diagrams
A long tape attached to a moving object and threaded through a device that places a tick upon the tape at regular intervals of time – leaving a trails of dots

3. Ticker Tape Diagrams
The distance between dots represents the object’s change in position during that time interval
small distance – slow moving Even distances = constant velocity
large distance – fast moving

4. Ticker Tape Diagram
A changing distance between dots indicates a changing velocity – acceleration

5. Graphing Motion

6. Graphing Motion
ZERO MOTION The object is at rest Position-time graph (x vs t) position of an object remains constant over time Velocity-time graph (v vs t) object is not moving, it has 0 velocity Acceleration-time graph (a vs t) If the object’s velocity is not changing, its acceleration is 0
The acceleration is zero because velocity is not changing not because the velocity is zero
Sketch above graphs

7. Graphing Motion
Uniform Motion – Constant Velocity x vs t graph as time increases so does the position *slope of a x vs t graph = velocity v vs t graph velocity remains constant over time *this should reflect the value of the slope of the x vs t graph a vs t graph velocity is not changing, acceleration is 0 *slope of a v vs t graph is acceleration
Steeper slope – faster velocity
Shallow slope – slower velocity

8. Graphing Motion Uniform Accelerated Motion
x vs t graph – position is increasing exponentially with time (acceleration)
v vs t graph – velocity is increasing with time (acceleration)
a vs t graph – acceleration is constant.
The value of a is equal to the slope of the v vs t graph
Acceleration will always be a horizontal line

9. Tangent Lines t On a position vs. time graph: SLOPE VELOCITY Positive
Position time graph x
Tangent Lines t
On a position vs. time graph:
SLOPE
VELOCITY
Positive
Negative
Zero
SLOPE
SPEED
Steep
Fast
Gentle
Slow
Flat
Zero

10. Increasing & Decreasing
Position time graph
Increasing & Decreasing t x
Increasing
Decreasing
On a position vs. time graph:
Increasing means moving forward (positive direction).
Decreasing means moving backwards (negative direction).

11. Concavity On a position vs. time graph:
Position time graph t x
Concavity
On a position vs. time graph:
Concave up means positive acceleration.
Concave down means negative acceleration.

12. Describe the motion
This object is moving in the positive direction and accelerating in the positive direction (speeding up).
This object is moving in the negative direction and accelerating in the negative direction (speeding up).
This object is moving in the negative direction and accelerating in the positive direction (slowing down).

13. Try this

14. Area under a v vs t graph
The area of a v vs t graph is displacement