8/31 Do Now
• Unit 2 Intro
• Car crash example
• Vocabulary
• Get out your name sign
• 2 sentences: A crumple zone on a car is the area in the
front which is designed to crumple in the event of a headon collision. Write two sentences on why you think this
would enhance passenger safety.
• Optional Challenge: In 1 km races, runner 1 on track 1(with
time 2 min, 27.95s) appears to be faster than runner 2 on track 2
(2min, 28.15s). However, length L2 of track 2 might be slightly
greater than length L1 of track 1. How large can L2-L1 be for us to
conclude that runner 1 is faster?
• A: 1.4m
Unit 2: 1-D Mechanics
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Movies: crumple zones & car accidents
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Volvo
Jeep
Rain
Snow & Ice
Essential Questions:
1. Why do cars have crumple zones?
2. Should your car’s gas pedal be called an ‘accelerator’?
3. When is a graph better than a formula to describe
motion?
4. What is the best way to stop an egg without breaking it?
5. How do traffic engineers design safe intersections?
Digital Textbook Installation
• See link on my web site
1-D Motion
• Graph of car’s velocity, acceleration, position
Safe Intersections
• Intersection scenario: blind curve with 200 ft.
before you can see the traffic light.
• Think-pair-share: What would you need to know
in order to design a safe intersection on a curvy
mountain road?
• Annotate the RFP
8/31 Closure/HW due Tuesday, 9/1
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Download and have parent sign Lab Safety Contract
Annotate the RFP and write out your questions about it
(Honors) Draw a graphs of the acceleration, velocity,
and position for a car with
1. Constant deceleration
2. Constant velocity
3. Constant position
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Notebook
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1: Do Now
1: Closure/HW
9/1 Do Now
• Request for Proposals
• Get out your name sign
• What factors would go into figuring out how to set
the speed limit on a curvy mountain road?
• Decide on which Scenario # (1 – 5) you want to
complete.
RFP: Safe Intersection
• Opportunity for challenge, creativity
• Questions about the RFP (save questions about your
design for later)
• Ethics Discussion
• You will have today, Wed/Thurs, and Friday to work on
this in class.
• You will present your case on Tuesday, Sept. 8
• You may work on it outside of class as much as you want.
• Group assignments: gather according to the difficulty
level you want to attempt
• In your groups, make a list of the information you need to
know in order to design this intersection.
Questions?
• What do you need to know in order to complete
this RFP?
(Optional): Demonstrate a, v, t
• In Section 2, write a scenario (constant a, v, x or
changing a, v, x) for your partner to demonstrate
then pair up and demonstrate.
Example: Dragster Roller Coaster
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Max speed: 120 mph (54 m/s)
Duration: 4.0 seconds
Calculate the acceleration. How many g’s is this?
Calculate the distance.
Graph a, v, and x vs. time
Symbols for position, velocity, acceleration
Average vs. instantaneous velocity
Displacement vs. distance
(Optional) Sample Problem
• Sample problem involving graph of a vs. t and x
vs. t. Derive equations of motion using the graph
and using calculus
9/1 Closure/Homework
HW Due 9/4
• List at least three (five) things you need to know
in order to design the intersection
• Displacement & Velocity Handout: Physics HW
#1: Problems 2, 4, 6, 10
• Tomorrow: Substitute
9/2-3 Do Now
• P2P Passwords
• Research for RFP
• HW
• To estimate the distance you are from a lightning strike, you can
count the number of seconds between seeing the flash and hearing
the associated thunderclap. For this purpose, you can consider the
speed of light to be infinite (it arrives instantly). Sound travels at
about 343 m/s in air at typical surface conditions. How many
kilometers away is a lightning strike for every second you count
between the flash and the thunder? How many miles is this? How
many miles per second is this?
• Ans: 0.343 km/s = 0.213 miles/s; 4.7 s/mi
• Optional Challenge: A bolt is dropped from a bridge under
construction, falling 90 m to the valley below the bridge. (a) In
how much time does it pass through the last 20% of its fall? (b)
What is the speed when it hits the ground?
• Ans: (a) 0.45 s; (b) 42 m/s
Digital Textbook Installation
• Web site link for the digital textbook installation
instructions
• 4th and 5th Period ONLY go to the LMC and pick
up textbooks as follows:
– Wed. Sept 2nd: 5th period - 11:20
– Thurs. Sept 3rd: 4th period - 9:40
In Class Assignment due Friday
• P2P Network Passwords
• Use your textbook, Ch. 2 as a reference for
designing your RFP and solving the Handout
problems
– Answer your questions from the Do Now using your
textbook or the internet
– Displacement & Velocity Handout: Physics HW #2:
Problems 11, 12, 13, 14, 15, 16, 17
Unit 2 Extra slides
One Dimensional (1D) Motion
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Position, distance, displacement
Velocity, acceleration
Average, instantaneous
Graphs: position, velocity, acceleration vs. time
Equations for constant acceleration
Computer Stuff
• Honors Physics web site:
http://www.peaktopeak.org/Content/Homework/all
en.hankla/Hankla.htm
• Infinite Campus U/N & PW
– Check grades
• P2P computer log-in U/N & PW
• Be sure to change your password to be the same
on both systems!
1D Motion Worksheet
• Pair up with your partner
• Work the first problem and check your answer
– If correct, move on to the next problem
– If incorrect, find your error
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Move to the next problem
Rows A & C start on Page 1
Rows B & D start on Page 2
Whatever problems you don’t finish during class are your
homework
Quiz Scores
• If you made less than 20/21, you MUST come to
my office hours on Monday at 3:10 to show me
that you understand the concepts
• The last 4 questions were treated as extra credit,
up to 21/21
8/20-21 Closure
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Write on an index card and turn in:
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Two things you learned today
One question you have
Homework due Friday: finish the page you
started in class
8/22 Do Now
Here is a velocity
vs. time graph
for an object:
1. Draw a graph of the acceleration vs. time
2. Draw a graph of the position vs. time
3. What is the value of the maximum
displacement?
4. What is the value of the maximum velocity?
Graph demonstrations
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Constant position
Change in position
Constant velocity
Change in velocity
8/22 Closure
•
Write on an index card and turn in:
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The best thing you learned this week
One question you have
One suggestion you have for me to do that would
improve your understanding
Homework due Monday
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Finish the front and back of the worksheet
Return SIGNED Lab Contract
• EQ: What is the difference between speed and
velocity?
– A: Direction
• Reinforcement
– Velocity is the slope of position
8/25 Do Now
• Think of an activity you enjoy doing.
• Draw a position-time graph of you doing it.
• Switch your graph with your partner and have
them draw the velocity-time graph of your activity.
• Switch back and see if you agree.
• See my example on the board if you need a
suggestion.
Lab Safety
• Review your Lab Safety Contract
• With your partner, draw a two scenes:
– One showing unsafe lab conditions and/or behaviors
– One showing safe lab conditions and/or behavior
• Share with the class
8/25 Demo/Closure
• Draw my position graph
• Draw my velocity graph
Essential Question
• What concepts in this unit are not understood?
8/26 Do Now
• Break into 4
groups,
according to
which question
you feel is the
hardest that you
can confidently
answer:
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Group 1: Find the distance traveled at t = 15 s
Group 2: Find the distance traveled and displacement at t = 45 s
Group 3: Find the displacement, velocity, acceleration at t = 45 s
Group 4: Find the distance, velocity, acceleration at t = 110 s
Do Now
• Break into 4
groups,
according to
which question
you feel is the
hardest that you
can confidently
answer:
• Group 1: Find the distance traveled at t = 15 s (A: 100m)
• Group 2: Find the distance traveled and displacement at t = 45 s (A:
distance: 100+150= 250 m; displacement: 100-150= -50 m)
• Group 3: Find the displacement, velocity, acceleration at t = 45 s (A:
disp = -50 m; v= 0 m/s; a = 3m/s2)
• Group 4: Find the distance, velocity, acceleration at t = 90 s (A: dist =
100+150+1050 = 1300 m; v = 15 m/s; a = -0.75 m/s2
Accelerating or Not?
• For each object, write down whether or not it is
accelerating. If it is accelerating, decide the value
and direction of the acceleration.
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Bus driving down Emma at 10mph
Bus on Emma approaching a stop sign at Public
Car driving down Spaulding at 10 mph
Car driving around parking lot at 5 mph
Bus leaving a stop sign on Emma, turning right on
Public
Unit 1 Concept Review Sheet
• Break into your six assigned groups
• For your topic, explain the things you feel are most
important to know on the whiteboard
• Share your results with the class
Practice
• Unit conversion
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1 parsec = 3.26 light years
light speed = 299792 km/s
1 light year = distance light travels in 1 year
Pico is the prefix for 10-12.
What is a pico-parsec in meters?
• Solve xf = xi + vt for t
• Solve xf = xi + vot + at2 for a
x
Position-Time Graph
A car travels along a
straight section of road.
A distance vs time graph
illustrating its motion is
graphed to the right.
(a) Indicate every time t
for which the car is at
rest.
5
b
c
f
a
5
15
10
5
d
e
Position Time Graph
(b) Indicate every time interval for which the speed of
the car is increasing.
(c) What is the velocity from: a to b, b to c, c to d, d to
e, and e to f?
t
Practice
• What’s the acceleration of the object whose
position at different times is noted below?
Time (s)
0
1
2
3
4
5
6
7
8
9
10
11
Distance (m)
0
1.5
6
13.5
24
37.5
54
73.5
96
121.5
150
181.5
Internet Resources
• Infinite Campus
– Logging in
– Checking grades and assignments
• Peak to Peak web site
– Checking homework assignments
• Information on CD-ROM Textbook
8/26 Closure
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Write the numbers 1 through 6 vertically on an
index card, representing each of the six concepts
on the review sheet. Next to each number, write:
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1 if you are confident you understand the concept;
2 if you are familiar with the concept but don’t feel
you fully understand it;
3 if you don’t understand it
Turn in the index card with the standard header
Homework due Wednesday
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Install textbook
Bring graph paper
8/27-28 Essential Question
• How do you measure velocity?
Velocity Lab
• Lab writeup is due in class TODAY!
• TEST on Tuesday, 9/2
• Homework due FRIDAY
– Read 2.0 through 2.6 in Principles of Physics (your
textbook)
– Do problems 2.7 & 2.8 in Principles of Physics (pages
19 & 21).
• For more preparation for the test, see Chapter 1
and Chapter 2.9 through 2.16
Practice
• Unit conversion
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1 parsec = 3.26 light years
light speed = 299792 km/s
1 light year = distance light travels in 1 year
Pico is the prefix for 10-12.
What is a pico-parsec in meters?
• Solve xf = xi + vt for t
• Solve xf = xi + vot + at2 for a
x
8/27-28 Closure
A car travels along a
straight section of road.
A distance vs time graph
illustrating its motion is
graphed to the right.
(a) Indicate every time t
for which the car is at
rest.
5
b
c
f
a
5
15
10
5
d
e
Position Time Graph
(b) Indicate every time interval for which the speed of
the car is increasing.
(c) What is the velocity from: a to b, b to c, c to d, d to
e, and e to f?
t
Essential Question
• Can you gain confidence with 1D motion
concepts?
8/29 Do Now
• Make a section in your notebook entitled
‘Reflections’
• Pull out
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notebook paper
graph paper
Pencil
Hard surface to write on (like a notebook)
• Write useful formulae on the top of your notebook
paper.
Practice
A ball is tossed straight up into the air at time t=0 s,
position xi = 0 m, and velocity vi = 5 m/s.
A) Draw the acceleration-time graph from t = 0 until
the ball returns to its original location.
B) Draw the velocity-time graph
C) Draw the position-time graph
If you missed any answers, you will start in
Group B
Practice
Same situation, but now:
D) Write the equation for acceleration as a function
of time [a(t)] over this time period
E) Write the equation for velocity over this time
period [v(t)]
F) Write the equation for position over this time
period [x(t)]
If you missed any questions and are not already
in Group B then you will start in Group C
Practice
Same situation, but now:
G) How long was the ball in the air?
H) What was the maximum height?
I) What was the total distance traveled?
J) What was the displacement?
If you got all the answers correct, you are in
Group D
Practice
Same situation, but now:
D) Write the equation for acceleration as a function of time
[a(t)] over this time period. A: a(t) = -9.8 m/s2
E) Write the equation for velocity over this time period
[v(t)]; A: v(t) = 5 m/s – (9.8 m/s2)t
F) Write the equation for position over this time period
[x(t)] A: x(t) = (5 m/s)t – (9.8 m/s2)t2/2
G) How long the ball was in the air? (A: 1.0 s)
H) Find the maximum height. (A: 1.3 m)
I)
What is the total distance traveled? (A: 2.6 m)
J)
What is the displacement? (A: 0 m)
Four-Corners
• Divide up into four groups around the room
– Group A needs practice on scientific notation, algebra,
or units
– Group B needs practice on graphical analysis
– Group C needs practice on using equations
– Group D is comfortable with the material for this unit
and wants a challenge
• If you finish with one Group, go on to the next
• Useful formulae
– a = v/t; v = x/t;
– v = at + vo ;
– x = vot + at2/2 (constant acceleration) = vt (constant
velocity)
Internet Resources
• Infinite Campus
– Logging in
– Checking grades and assignments
• Peak to Peak web site
– Checking homework assignments
• Information on CD-ROM Textbook
8/29 Closure
• Create a ‘Reflections’ section in your notebook
• I will grade this periodically
• Write out the useful formulae and an explanation
for each term
5/12 Do Now
Agenda
• Calendar
• Exam Review
41.C.2 Suppose two different hydrogen atoms, labeled
A and B, have their electrons in state n = 4. Atom A
emits light when its electron transitions directly
from the n = 4 state to the n = 2 state. Atom B emits
light twice, as its electron first transitions from the
n = 4 state to the n = 3 state, then transitions from
the n = 3 state to the n = 2 state. (a) Are the three
wavelengths of light the same or different? (b) How
does the energy of the photon from atom A compare
to the total energy of the two photons from atom B?
Q: What will I need to know in this class?
• A: Everything. Physics is the most basic science and does
not draw artificial boundaries between itself and biology,
chemistry, engineering, or any other technical discipline.
Math is the language of physics and English is the
language we use to communicate. You will also need
your common sense, observations about the real world,
and logic.
• It is not possible to list all the applications for a given
concept; therefore, you may see problems on the test that
involve situations we have not studied in class.
Q: Can I use my calculator?
• A: Sometimes. I have found that calculators often get in the way of
intuitive understanding and that many students cannot use them for
accurate calculations. So, I expect you to be able to perform
estimates of calculations without using your calculator; this will
enable you to do ‘smell checks’ on your final answer.
• Tests will often consist or sections in which calculators are not
allowed and other sections in which they are. Alternatively, I may
allow calculators only during the last 10 minutes of a test.
• It is your responsibility to be able to use your calculator accurately
– I will not spend any class time on this. If you need help, come to
office hours.
Q: Will you provide review sheets for tests?
• A: No. However, I will guide you as you make
your own. Prior to each unit, I will give you the
unit objectives so you will know what is
important. During each unit, you will work
problems in the Do Nows, lessons, and homework
and these will serve as guides for test review.
Q: What if I’m not challenged?
•
A: It is my responsibility to make opportunities
available for you to challenge yourself; I will lay
these opportunities at your feet. It is your
responsibility to pick them up; if you choose not
to, that’s fine, but no complaining.
Q: How will I know if I understand the unit well enough for
the test?
• Level 1: Regurgitation
– Prepare by changing numbers from Do Now and HW problems and solve
– If you can do this, you should expect a low C
• Level 2: apply concepts in different situations and/or connect
multiple concepts to solve a problem
– Prepare by modifying Do Now and HW problems for different situations or
by working different end-of-chapter problems
– If you can do this, you should expect an A or a B
• Level 3: apply concepts to the real world
– Prepare by analyzing a real-world situation using the concepts in the unit.
Ask yourself: How does a truss work? Why is the sky blue? What limits
solar cell efficiency? What would the earth be like without greenhouse
gasses? How would I use the concepts in this unit to improve a car?
– If you can do this, you should expect an A or a B
Calendar
5/12
5/13-14
5/15
5/18
5/19
5/20-21
5/22
5/26
Exam Review
Exam Review
Presentations & Exam Review
Relativity (optional) or Exam Review
Relativity (optional) or Exam Review
Remaining presentations and Exam Review
Finals for 1st period
Finals for 2nd and 4th periods
Test grade expectations
• What would be an appropriate level of
understanding in order to get a C?
– Level 1: Regurgitation
– Prepare by changing numbers from Do Now and HW
problems and solve
• What about an A?
– Level 2: apply concepts in different situations.
– Prepare by modifying Do Now and HW problems for
different situations or by working different end-ofchapter problems
Options for review
1. Need more practice: Get a book and start working even
numbered problems. Start building your review sheet.
•
Your ticket out the door will be to show me your solutions to 5
problems not from the HW already assigned.
2. Comfortable with material, just need to build review
sheet
•
Your ticket out the door will be to show me your review sheet
with at least one side filled in
3. Comfortable with the material, looking for a challenge.
•
Your ticket out the door will be to show me your solutions to
the Closure.