1. Introduction to Mechanics 2.1 notes
LEAP DAY!!!
February 29, 2016
Introduction to Mechanics 2.1 notes

2. Warm up
As a table, discuss and come up with a definition for MOTION

3. Aristotle 384-322 BC Old Greek Philosopher He lived from 384-322 BC
He studied from Plato in his academy for 20 years
He became the tutor of young Alexander the Great

4. Aristotle on Force
A force is required to keep an object moving
2000 years pass….

5. Alexandrian Conquest

6. Roman Conquest

7. Crusades

8. Dark Ages

9. Galileo 1564-1642 Lived from 1564-1642 AD
He made a big discovery that proved Aristotle was wrong
Dropped two weight objects and they both landed at the same time
So Aristotle must have been wrong about forces being necessary to keep objects moving.
Galileo said that force is required to START an object moving, but none is required to keep it moving
(when there isn’t friction)

10. Inertia Objects in motion want to stay in motion
Objects at rest want to stay at rest
Unless acted on by another force.

11. Mass and Inertia Mass is actually a measurement of inertia.
More mass = more inertia
Less mass = less inertia

12. Check it out… https://www.youtube.com/watch?v=vfnt8Sdj7cs
Inertia Demos:
Redo inertia “magic trick” with hoop and pennies/dice
Paint stick and newspaper karate chop
Hammer and bowling ball
Card and poker chips
Magic Broom
Meter vs Newton-Meter drop

13. Lesson Recap A ball rolling on a pool table slowly comes to a stop.
How would Aristotle explain this behavior?
How would Galileo explain it?
How would you explain it?

14. Reaction Time Activity
Work with partner at table group
Record distance in METERS please
In your analysis---EVERY number needs a unit!
Discuss the discussion questions
(you don’t need to write anything down)
Done early? Do the extra challenge!

15. Speed vs. Velocity Distance vs. Displacement Definitions of Δ and (-)
March 3, 2016
Speed vs. Velocity
Distance vs. Displacement
Definitions of Δ and (-)

16. Speed Speed is a scalar quantity Formula: 𝑆𝑝𝑒𝑒𝑑= 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑖𝑚𝑒
Scalar means it is just a number without direction
Formula:
𝑆𝑝𝑒𝑒𝑑= 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑡𝑖𝑚𝑒

17. Velocity Velocity is a vector quantity Formula:
Vector means it has both a number AND direction
Formula:
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦= ∆ 𝑑𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡 ∆ 𝑡𝑖𝑚𝑒
Δ means “change in” which is calculated = (final – initial)
( - ) in physics just indicates direction

18. Distance vs. Displacement
Distance (scalar)
Is how much ground an object has covered
Displacement (vector)
Is the overall change in position
Watch this!
Now let’s try it!
Practice Questions—write on white boards

19. Maps Graphs Instantaneous vs. Average
March 7, 2016
Maps
Graphs
Instantaneous vs. Average

20. Motion Maps Each dot represents the position at an equal time interval
Use the space below this definition in your notes to draw in a sample motion map…
Bowling lab with sticky notes
Jogger vs. sprinter
Make up your own

21. Graphs Position vs. Time graphs---Slope = velocity value
As demonstrated in your Dance Party Lab

22. Average vs. Instantaneous
“Average” velocity is a measure of the total distance traveled in a certain period of time.
“Instantaneous” velocity is the exact speed at a specific point in time
Example:
I went to see Zootopia with a gaggle of junior high girls from my church on Saturday. It took me 10 minutes to get from church to the theater 3 miles away.
My average speed was:____________
My instantaneous speed was all over the place.

23. March 16, 2016
Acceleration

24. Translations Recall that on a displacement vs. time graph
SLOPE = VELOCITY value
But what about the slope of a velocity vs. time graph?
(Think about your Tickticktick lab and yesterday’s instantaneous velocity activity)
What are the units?
What does the measurement mean?

25. Acceleration (vector)
The formula for acceleration is:
𝐴𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛= ∆ 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 ∆ 𝑡𝑖𝑚𝑒
In a velocity vs. time graph
SLOPE = ACCELERATION value

26. Summary of how to represent motion in graphs

27. Review Day Tasks: Tom’s graph matching (create acceleration vs. time)
Update Instantaneous Velocity Activity (turn in)
Check answer key for Acceleration Practice at front (turn in)
4. Work on any missing work or make up labs
5. Go over missing work with Mrs. Peterson when called

29. Test Corrections Instructions
Use a different color than your original writing
Write directly on test (unless not enough room)
Write the correct answer
AND EXPLAIN WHY IT IS CORRECT
Return directly to Mrs. Peterson
Absolutely NO phones in class today at all
This is your only warning…