1. Chapter 10: Motion The BIG idea:
The motion of an object can be described and predicted
Key Concepts:
10.1: An object in motion changes position
10.2: Speed measures how fast position changes
10.3: Acceleration measures how fast velocity changes

2. While I check your HW: Turn to page 309
On a “small” (not too small) piece of paper please select the unit project you would like to work on…

3. Chapter 10: Motion 10.1 An object in motion changes position
10.2 Speed measures how fast position changes
10.3 Acceleration measures how fast velocity changes

4. 10.1 An object in motion changes position
Section Concepts:
How to describe an object’s position
How to describe an object’s motion
Give directions to an object in the classroom…
What kinds of information must you give another person when you are trying to describe a location?
Compare the location of the object with the location of another object or place

5. Position describes the location of an object
Position – the location of a place or object
Often described by comparing an objects position with where you currently are
You need to discuss two locations to describe the position of an object – to compare

6. Describing a position
Reference point – a location to which you compare other locations
Points on a graph
Latitude: how many degrees north or south a location is from the equator
Longitude: how many degrees east or west a location is from the prime meridian

7. Measuring distance
The actual distance traveled depends on the path taken, not just the distance from point A to point B
The standard unit of length is the meter (m) = 3.3 feet (ft)
Also useful: kilometers (1000 m = 1 km)
centimeters (1 m = 100 cm)

8. Motion is change in position
Motion – the change of position over time
Horizontal
Vertical
(p. 315) A change in position is evidence that motion happened
How does the picture show time passing?
it shows the jumper in a number of different positions between the start and finish
How is the picture different from a snapshot?
a snapshot freezes a single moment in time

9. Describing Motion
A change in an object’s motion tells you that motion took place
Tells you nothing about how quickly the object changed positions – it’s speed (or, velocity)
Velocity is speed plus direction
A faster object moves farther than a slower moving object would in the same amount of time
Standard unit of measurement for speed/velocity: meters/second
Velocity equals Distance over time: v = d/t
Velocity: meters/second…distance: meters…time: seconds

10. Relative Motion Sit still in a chair: are you moving?
Depends on the position and motion of the person observing you
Observer leaves Earth – you are moving!
How an observer sees your motion depends on how it compares with his own motion
Motion is described using the reference point…or “frame of reference”
“frame of reference”: the location of an observer, who may be in motion also

11. Relative Motion
Picture a student on a moving bus passing a student on the street (p.317)
The observer on the bus does not see the driver changing position, but the street sign appears to move pass the window
The observer on the street sees the driver changing position along with the bus, but the street sign appears to remain in the same position
**All motion is measured relative to an observer’s frame of reference
-an object not moving in one frame of reference will be moving in another

12. Relative Motion
Suppose you are on a train, and you cannot tell if you are stopped or moving. Outside the window, another train is slowly moving forward. Could you tell which of the following is happening?
Your train is stopped, and the other train is moving slowly forward
The other train is stopped, and your train is moving slowly backward
Both trains are moving forward, with the other train moving a little faster
Your train is moving very slowly backward, and the other train is moving very slowly forward
All would look the same to you!!! – unless you compared the motion to the motion of something outside the train

13. Investigate: Changing Position (p
Investigate: Changing Position (p. 316) How are changes in position observed?
Lab notebooks:
Follow procedure, make sketches AND graphs (time vs height) of your observations
Answer: “What do you think?” and “Challenge”
End of Section 10.1 Review p. 318 # 5, 6