8/31 Do Now

• 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 head-on 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 Intro

• Car crash example

• Vocabulary

Unit 2: 1-D Mechanics

• Movies: crumple zones & car accidents– 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

• 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

• Notebook– 1: Do Now

– 1: Closure/HW

9/1 Do Now

• 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.

• Request for Proposals

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

• 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

• 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

• P2P Passwords

• Research for RFP

• HW

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

• 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/allen.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

• 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

• Write on an index card and turn in:– Two things you learned today– One question you have

• Homework due Friday: finish the page you started in class

8/22 Do NowHere 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

• Constant position

• Change in position

• Constant velocity

• Change in velocity

8/22 Closure

• Write on an index card and turn in:– 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– 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:

• 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.– 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– 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

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.

t

x

Posit ion T ime Gr aph

a

b

5

5

10 15

c

5d e

f

(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?

Practice• What’s the acceleration of the object whose

position at different times is noted below?Time (s) Distance (m)

0 01 1.52 63 13.54 245 37.56 547 73.58 969 121.5

10 15011 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

• 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:

– 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

– 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– 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

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.

t

x

Posit ion T ime Gr aph

a

b

5

5

10 15

c

5d e

f

(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?

Essential Question

• Can you gain confidence with 1D motion concepts?

8/29 Do Now

• Make a section in your notebook entitled ‘Reflections’

• Pull out – notebook paper– graph paper– Pencil– Hard surface to write on (like a notebook)

• Write useful formulae on the top of your notebook paper.

PracticeA 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

PracticeSame 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

PracticeSame 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

PracticeSame 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

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?

Agenda

• Calendar

• Exam Review

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 Exam Review5/13-14 Exam Review5/15 Presentations & Exam Review5/18 Relativity (optional) or Exam Review5/19 Relativity (optional) or Exam Review5/20-21 Remaining presentations and Exam Review5/22 Finals for 1st period5/26 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-of-chapter 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.