1. DESCRIBING MOTION
POSTION AND MOTION

2. STANDARD
8. PS MATTER AND STABILITY: FORCES AND INTERACTIONS
Create a demonstration of an object in motion and describe the position, force, and direction of the object.

3. LEARNING OBJECTIVES
Describe an objects position based on its reference point. 01
Describe a position in both one and two dimensional. 02
Know the difference between distance and displacement. 03

4. DESCRIBING POSITION
Reference point is the starting point you choose to describe the location, or position of an object.
Describing your location also includes your distance and direction from the reference point.
A position is an object’s distance and direction from a reference point.

5. CHOOSING A REFERENCE POINT
Choose a reference point that a person can easily find.
Describe the direction from that reference point.
Describe the distance from that reference point.

6. Changing the reference point changes the distance of an object’s position. The position does not change.
The reference direction
Sometimes the words positive and negative are used to describe direction.
The reference direction is the (+) direction.
The opposite direction is the (-) direction.
REFERENCE DIRECTION

7. TWO DIMENSIONAL
Describing a position using two directions, you are using two dimensions.
Example: North and East or South and West
Example: Up and Right or Down and Left

8. LOCATING A POSTION IN 2D
Choose a reference point
Specify reference directions, ex: North and East
Determine the distance along each reference direction.

9. DESCRIBING CHANGES IN POSITION
Sometimes you need to describe how an object’s position changes.
Motion is the process of changing position.
Motion relative to a reference point
If an object’s distance has changed relative to a reference point, the object is in motion.

10. DISTANCE & DISPLACEMENT
Distance is the length of the path an object takes.
Displacement is the difference between the initial (first) position and the final position of an object.
The distance and displacement are equal only if the motion is in one direction.
DISTANCE & DISPLACEMENT

11. DESCRIBING MOTION
SPEED & VELOCITY

12. STANDARD
8. PS MATTER AND STABILITY: FORCES AND INTERACTIONS
Create a demonstration of an object in motion and describe the position, force, and direction of the object.

13. 01 02 03 LEARNING OBJECTIVES Know what speed is.
Use a distance-time graph to calculate average speed. 02
Know how velocity can change. 03

14. WHAT IS SPEED?
A way you can describe how fast you move is to determine your speed.
Speed is a measure of the distance an object travels per unit of time.
You calculate speed by dividing distance traveled by the time it takes to go that distance.
The SI units for speed is meters per second or (m/s).
Other examples: km/h = kilometers / hour
mph = miles / hour

15. CONSTANT SPEED
Moving the same distance per amount of time, speed is NOT changing.
Constant Speed is the rate of change of position in which the same distance is traveled each second.
Example: Cruise Control in your vehicle

16. CHANGING SPEED
Moving a different distance per amount of time, speed IS changing.
If speed of an object is not constant, you might want to know its speed at a certain moment.
Instantaneous Speed is speed at a specific instant in time.
Example: Looking at the speedometer

17. AVERAGE SPEED
Average Speed is the total distance traveled divided by the total time taken to travel that distance.
b. Formula: v = average speed (m/s)
d = distance traveled (m) t = total time (s)

19. AVERAGE SPEED PRACTICE
EXAMPLE 1
EXAMPLE 2
It takes Ahmed 50s on his bicycle to reach his friends house 250m away.
What is his average speed?
5 m/s
A truck driver makes a trip that covers 2,380km in 28 hours.
What is the driver’s average speed?
85 km/hr

20. DISTANCE – TIME GRAPHS
Graphs that show comparisons between distance and time are called Distance - time graphs.
Distance-time graphs are used to compare two different objects, calculate speed, & the changing of speed.
Slowing down – downward curve
Stopping – horizontal line
Speeding up – upward curve
Average speed – 1) Choose a starting point & ending point,
2) Find the change in distance & change in time between the two points
3) Find the average speed.

21. DISTANCE – TIME GRAPHS COMPARING TWO OBJECTS Question Question
1) How fast was the horse traveling ) Which horse was faster?
in km/s? km/s horse A

22. DISTANCE – TIME GRAPHS
CALCULATING SPEED

23. DISTANCE – TIME GrAPHS
CHANGING SPEEDS

24. VELOCITY Velocity is the speed and the direction of a moving object.
Representing Velocity
Velocity can be represented by an arrow. The length of the arrow indicates the speed. The bigger the arrow, the greater the speed. The arrow points in the direction of the objects motion.
You can have the same speed, but different velocity based on going a different direction.
VELOCITY

25. In a moving object, the changes of the arrows length mean the velocity is constantly changing.
Velocity changes when the
1) Speed of an object changes
2) Direction that the object moves changes
3) BOTH speed and direction change.
CHANGING IN VELOCITY

26. FIRST THING TO DO LIST HAVE YOUR MOTION VOCABULARY OUT TO GO OVER
WRITE DOWN YOUR HOMEWORK
Lesson 1 Position & Motion pg. 45 & 46

27. DESCRIBING MOTION
ACCELERATION

28. STANDARD
8. PS MATTER AND STABILITY: FORCES AND INTERACTIONS
Create a demonstration of an object in motion and describe the position, force, and direction of the object.

29. 01 02 LEARNING OBJECTIVES Know the 3 ways an object can accelerate.
Know what a speed - time graph indicate about an object’s motion. 02

30. ACCELERATION CHANGES IN VELOCITY
When an object’s velocity changes, the object is accelerating.
Acceleration is a measure of change in velocity during a period of time.
An object accelerates when
1) Increasing speed
2) Decreasing speed
3) Changing direction.

31. CALCULATING ACCELERATION
Acceleration is a change in velocity divided by the time interval during which the velocity changes.
FORMULA: a = acceleration (m/s²) vf = final speed (m/s)
vi = initial speed (m/s) t = total time (s)

33. ACCELERATION PRACTICE
EXAMPLE
Aidan drops a rock from a cliff. After 4.0s, the rock is moving at39.2 m/s.
What is the acceleration of the rock?
9.8 m/s²

34. Object at Rest
SPEED – TIME GRAPHS

35. Constant Speed
SPEED – TIME GRAPHS

36. Speeding UP
SPEED – TIME GRAPHS

37. Slowing DOWN
SPEED – TIME GRAPHS

38. SURPRISE!!!!!!! POP QUIZ
__________________ is a measure of change in velocity during a period of time.
__________________is a measure of the distance an object travels per unit of time.
TRUE OR FALSE
You can have the same speed and velocity going the same direction. _____________
You can have the same speed and velocity going different directions. _____________
In a moving object, velocity does not change. _____________
Which of the following formulas do we use to find average speed? B.