Class 86.5 

Warm-Up: 

1.  How does a "Frisbee" work?

2.  Why is "Frisbee" in quotation marks?

3.  Typical sport discs tend to roll over in the air.  Which way do they roll over?

4.  What causes a disc to roll over and how can you prevent it?

Homework: 

• Prepare for the final exam.

Class 86 

Warm-Up: 

1.  Why can't humans see clearly under water?

2.  Guess which condition (on the right) makes it easier to see clearly under water?

3.  Goggles and masks can be used to see clearly under water, but they distort the observed heights of objects.  Do they magnify or reduce?  Why?

Homework: 

• Prepare for the final exam.

Class 85.5 

Warm-Up: 

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• Prepare for the final exam.

Warm-Up: 

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• Prepare for the final exam.

Class 84.5 

Warm-Up: 

The index of refraction (n) of a substance varies with the wavelength of the waves passing through the substance.  This phenomenon causes dispersion, which is the separation during refraction of light rays of different color. 

1.  What are the colors of visible light, in order of wavelength?

2.  If n decreases with increasing wavelength, where will the different colors emerge from this prism?

Scattering is the phenomenon whereby light "bounces off" of particles (e.g. N₂ molecules, ice crystals, and smoke) in the sky.  Shorter wavelengths of light are more susceptible to scattering than longer wavelengths.

2.  Why is the sky blue?

3.  Why are sunsets red?

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• Prepare for the final exam.

Class 84 

Warm-Up: 

1.  Why can't the observer see the penny? (and why can't you see the fish in the tank in the back of the room?)

2.  How can we make the penny or the fish visible by adding just one component to the system?

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• Optics practice quiz

• Prepare for the final exam.

Warm-Up: 

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• None

Class 83 

Warm-Up: 

If look in a mirror while wearing a shirt that says "shirt," the image will appear flipped.  Across which mirror plane will it appear to have been flipped?  Why that one?  Why not some other mirror plane?

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• Practice (with answers) -- Ch 25.3-25.4

• If your instrument project is not complete, insert a slide at the beginning that says "Do Not Grade."  You'll have a zero, but there won't be a permanent grade deduction for one week.  After midnight tonight, you'll lose 10% for lateness.

Class 82.5 

Warm-Up: 

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• Practice 25.1-25.2  Solutions

• If your instrument project is not complete, insert a slide at the beginning that says "Do Not Grade."  You'll have a zero, but there won't be a peranent grade deduction for one week.  After midnight tomorrow, you'll lose 10% for lateness.

Warm-Up:  No Warm-up.  Test today.

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• Sound and waves test tomorrow

• If your instrument project is not complete, insert a slide at the beginning that says "Do Not Grade."  You'll have a zero, but there won't be a peranent grade deduction for one week.  After midnight on Wednesday, you'll lose 10% for lateness.

• Doppler Challenge on Tuesday -- for extra points added to the project.  Listen to three recordings of speeding cars and calculate their speeds.  You may use your instrument, your ears, a calculator, paper, and pencil.

Warm-Up: 

Today: 

Reading:  

• Ch 25.1 -- Ray Aspect of Light

• Ch 25.2 -- Law of Reflection

Homework: 

• Sound and waves test tomorrow

• If your instrument project is not complete, insert a slide at the beginning that says "Do Not Grade."  You'll have a zero, but there won't be a peranent grade deduction for one week.  After midnight next Wednesday, you'll lose 10% for lateness.

• Doppler Challenge on Tuesday -- for extra points added to the project.  Listen to three recordings of speeding cars and calculate their speeds.  You may use your instrument, your ears, a calculator, paper, and pencil.

Warm-Up:   None

Today: 

Homework: 

• Sound and waves test on Friday

• Instrument Projects are due by midnight tonight.  If your project is not complete, insert a slide at the beginning that says "Do Not Grade."  You'll have a zero, but there won't be a peranent grade deduction for one week.  After 1 week, you'll lose 10% for lateness.

• Quiz corrections for the magnetism quiz are due today.

Class 80.5 

Warm-Up:   

3. 7/8 onlyHow can you write a simple song (that sounds like a song)? 

Today: 

Music and Ukulele Info/links:

• Good source for ukulele chords -- Ukutabs.com

• Some simple songs -- 4 chords or fewer:  She Will Be Loved,  Folsom Prison Blues, Knockin on Heaven's Door, I'm Yours, Wagon Wheel, Viva La Vida, Free-Fallin (fast chord changes), The Joker, Have It All, Yellow (Cold Play -- one extra chord at very end),  Riptide, Happy Birthday, Radioactive, Smells Like Teen Spirit, Somebody That I Used To Know

• String Mass/Length Ratios (for string tension slide)  Don't forget to estimate stretch: 

  • 100# line -- frets (0.00075kg/m),

  • 80# line -- C string (0.00059kg/m),

  • 60# line -- E string (0.00031kg/m), 4

  • 0# line -- G and A string (0.00026kg/m). 

• One way to write a simple song:

  • Find a chord progression that you like

  • Play the chord progression in the key of C

  • Add a melody using mostly the notes that are in the chords (your ear might help you do this without really thinking about the notes)

  • You can record a chord progression in audacity by playing it on the Virtual Piano and using the WASAPI audio host setting.  Export the progression and then play it as a loop while you try out melodies along with it. 

• Chord progressions:

  • Popular chord progressions:  1-6-4-5, 1-5-6-4... 

  • "...great chord progressions"

  • General chord progression information

  • C-major chord numbers 

  • C major chords finger positions, corresponding to chords 1-6 in the chart above.

• Virtual Piano

Homework: 

• Sound and waves test on Friday, May 24th. 

• Instrument Projects are due on Wednesday.

• Quiz corrections for the magnetism quiz are due on Wednesday.

Class 80 

Warm-Up:   

1. What do the waves on the right sound like? link won't work on school wifi

2. How many of these waves could actually exist?

3. How can you write a simple song (that sounds like a song)? 

Today: 

Resonance Lab:

• Effects of temperature on instrument frequency

• Tuning forks and temperature

• Human voice

Music and Ukulele Info/links:

• Good source for ukulele chords -- Ukutabs.com

• Some simple songs -- 4 chords or fewer:  She Will Be Loved,  Folsom Prison Blues, Knockin on Heaven's Door, I'm Yours, Wagon Wheel, Viva La Vida, Free-Fallin (fast chord changes), The Joker, Have It All, Yellow (Cold Play -- one extra chord at very end),  Riptide, Happy Birthday, Radioactive, Smells Like Teen Spirit, Somebody That I Used To Know

• String Mass/Length Ratios (for string tension slide):  100# (0.75g/m), 80# 0.59g/m, 60# (0.31g/m), 40# (0.26g/m).  Don't forget to estimate stretch.

• One way to write a simple song:

  • Find a chord progression that you like

  • Play the chord progression in the key of C

  • Add a melody using mostly the notes that are in the chords (your ear might help you do this without really thinking about the notes)

  • You can record a chord progression in audacity by playing it on the Virtual Piano and using the WASAPI audio host setting.  Export the progression and then play it as a loop while you try out melodies along with it. 

• Chord progressions:

  • Popular chord progressions:  1-6-4-5, 1-5-6-4... 

  • "...great chord progressions"

  • General chord progression information

  • C-major chord numbers 

  • C major chords finger positions, corresponding to chords 1-6 in the chart above.

• Virtual Piano

Homework: 

• Sound and waves test will be next Friday, May 24th. 

• Instrument Projects are due next Wednesday, May 22nd.

• Quiz corrections for the magnetism quiz are due on Wednesday, May 22nd.

Class 79.5 

Warm-Up:   

1. A glass soda bottle can be a simple wind instrument.  Does the bottle's pitch change with air temperature?  (what about the wavelengths of its sound waves?)

2. Does a tuning fork's pitch change with air temperature?  (what about the wavelengths of its sound waves?)

3. What kind of instrument is the human voice?  Does the human voice's pitch change with air temperature?  (what about the wavelengths of its sound waves?)

Today: 

Music and Ukulele Info/links:

• Good source for ukulele chords -- Ukutabs.com

• Some simple songs -- 4 chords or fewer:  She Will Be Loved,  Folsom Prison Blues, Knockin on Heaven's Door, I'm Yours, Wagon Wheel, Viva La Vida, Free-Fallin (fast chord changes), The Joker, Have It All, Yellow (Cold Play -- one extra chord at very end),  Riptide, Happy Birthday, Radioactive, Smells Like Teen Spirit, Somebody That I Used To Know

• String Mass/Length Ratios (for string tension slide):  100# (0.75g/m), 80# 0.59g/m, 60# (0.31g/m), 40# (0.26g/m).  Don't forget to estimate stretch.

Homework: 

• One additional practice test problem: Assuming that the bridge-to-nut distance for this ukulele is 40cm, what how far should the 7th fret be placed from the nut? 

• Sound and waves test will be next Friday, May 24th. 

• Instrument Projects are due next Wednesday, May 22nd.

• Quiz corrections for the magnetism quiz are due on Wednesday, May 22nd.

• The practice test is due on Friday.  Sound and Waves Practice Test.  Solutions to all except the last problem.

Class 79 

Warm-Up:   

1.  What is a chord?

2.  What chord is being played on the rigtht?

3.  Why do some combinations of musical notes sound nice together, while others do not?

4.  What is just intonation?

• Where Math Meets Music

• Frequency ratios page

Today: 

Ukulele Info:

• Good source for ukulele chords -- Ukutabs.com

• Some simple songs -- 4 chords or fewer:  She Will Be Loved,  Folsom Prison Blues, Knockin on Heaven's Door, I'm Yours, Wagon Wheel, Viva La Vida, Free-Fallin (fast chord changes), The Joker, Have It All, Yellow (Cold Play -- one extra chord at very end),  Riptide, Happy Birthday, Radioactive, Smells Like Teen Spirit, Somebody That I Used To Know

• String Mass/Length Ratios (for string tension slide):  100# (0.75g/m), 80# 0.59g/m, 60# (0.31g/m), 40# (0.26g/m).  Don't forget to estimate stretch.

Homework: 

• Quiz corrections for the magnetism quiz are due on Wednesday, May 22nd.

• The practice test is due on Friday.  Sound and Waves Practice Test.  Solutions to all except the last problem.

Warm-Up :   

Today: 

Online Textbook Reading:   17.4 -- Doppler Shift and Sonic Booms

Homework: 

• Quiz corrections for the magnetism quiz are due on Wednesday, May 22nd.

Class 77.5 

Warm-Up :   

Today: 

Links:

• Harmonics played on a violin (video)

• Harmonics played on a flute (video)

Online Textbook Reading:   17.4 -- Doppler Shift and Sonic Booms

Homework: 

• Quiz corrections for the magnetism quiz are due on Wednesday, May 22nd.

• Bring your instrument tomorrow.

• Get a tuner app.  There are many free ones.

Warm-Up :   

Today: 

Links:

• Harmonics played on a violin (video)

• Harmonics played on a flute (video

Online Textbook Reading:   17.4 -- Doppler Shift and Sonic Booms

Homework: 

• 17.4 Practice. solutions

• Complete Measuring Speeds Using Musical Instruments.   Listen to these changes in pitch.  Pretend that the changes in pitch represent a Doppler shift for a moving vehicle.  Using this Virtual Piano or your string instrument, try to determine the number of half steps by which the pitches changed.  Contrary to how intervals are named in the context of music, count only the half steps that represent change.  Answers:  A -- 48.8m/s   B -- 86.4m/s   C -- 29.4m/s

Class 76.5 

Warm-Up :   

Today: 

Links:

• Harmonics played on a violin (video)

• Harmonics played on a flute (video)

Online Textbook Reading:  16.9 -- Waves

Homework: 

• None

Class 74.5 

Warm-Up :   

1. How does a bow cause a string to vibrate at its resonant frequency?
2. Why does it help to wet your finger when you make sound by rubbing the rim of a wine glass?

3.  Calculate the speed of sound when the temperature is 25 degrees Celsius.  You can use either formula below.

Today: 

• Get set for tomorrow.
• Get practice problems: 
  • Practice #1:  16.9 Practice Solutions
  • Practice #2: Ch 16.10 and 17.5 practice  Solutions.
• To solve the practice problems, you may need to refer to your earlier notes.  Here are the sound/waves notes so far...
  • Old notes -- Notes: Wave and Music theory relating to fret calculations -- and fret practice -- shorten to focus only on fundamental  Filled-in notes
  • New notes -- Sound and Waves Notes, Part 2  Filled-in version

Links:

• Harmonics played on a violin (video)

• Harmonics played on a flute (video)

Online Textbook Reading:  16.9 -- Waves

Homework: 

• Quiz tomorrow over magnetism notes, right hand rules, and Lenz's Law.

• Corrections for the last test (current and circuits) are due by next Tuesday (5/7)

• Homework due on Monday

  • Practice #1: 16.9 Practice Solutions
  • Practice #2: Ch 16.10 and 17.5 practice  Solutions

Class 74 

Warm-Up :   

1.  Identify any nodes and/or antinodes in this video of the "wave pool."

2.  Which harmonic is this?  Could there be other harmonics?

3.  Two important wave-related terms are resonance and forced vibrations.  What do the two terms mean, and how are they related?  Which one applies to the body of an instrument?  Which one applies to breaking glass with your voice?  How about the Tacoma Narrows Bridge collapse? 

• Tacoma Narrows Bridge collapse -- Old footage

• Tacoma Narrows Bridge collapse -- Discussion

Today: 

• Quiz update:  there will be no penalty for guesses, and corrections will be the usual type.  You must explain why.  Here are some sample quiz questions with improved diagrams.
• Finish notes  Sound and Waves Notes, Part 2  Filled-in version
• Finish collecting resonance lab data.  Perform calculations.
• Discuss the instrument project -- Instrument Project Guidelines and Grading  Example project with everything except Chladni patterns and string tensions

Online Textbook Reading:  16.9 -- Waves

Homework: 

• Quiz on Friday over magnetism notes, right hand rules, and Lenz's Law.

• Corrections for the last test (current and circuits) are due by next Tuesday (5/7)

4/30/19

Warm-Up :   

Today: 

• Check/review homework --  Right Hand Rule and Lenz's Law practice  Answers
• Finish collecting resonance lab data.

Online Textbook Reading:  16.9 -- Waves

Homework: 

• Quiz on Friday over magnetism notes, right hand rules, and Lenz's Law.

• Sign up for flex to fix instruments.  RB PS, JG, LC LM, PI JG MB, JB, PG PW JD, HW, YN JB, EW JW TE,

Warm-Up :    The picture on the far right shows a transformer.  The picture on the near right shows a simplified transformer.  The two coils of insulated wire are not connected to one another.  There is a wire connecting one of these to your home.

1.  What does a transformer do?

2.  Transformers work with alternating current (A.C.).  If the left coil's current (shown in the diagram) is increasing at this moment, what is the direction of the current in the coil on the right?

3.  The purpose of these transformers is to "step down" the high voltage in the transmission lines to a lower voltage that enters your home.  Why do the transmission lines need to have such high voltage?

4.  A table saw uses 3,000W, and it can be wired for 120V or 240V.  What are the pros/cons of each voltage?

Today: 

• Check/review homework --  Right Hand Rule and Lenz's Law practice  Answers
• Note about Friday -- Mr. Stapleton will be gone. 
  • Quiz
  • Work time
    • Finish motor.  If you already have credit, disassemble your motor.
    • Instrument project
• Get Right Hand Rules and Lenz's Law, practice #2 Answers
• Back to waves and sound:
  • Prior notes -- Notes: Wave and Music theory relating to fret calculations -- and fret practice -- shorten to focus only on fundamental  Filled-in notes
  • New notes -- Sound and Waves Notes, Part 2  Filled-in version
  • String standing waves demo.  How how harmonics can be found by varying either string length or vibrational frequency.
  • Complete resonance lab at the end of the waves notes

Links:

Online Textbook Reading:  16.9 -- Waves

Homework: 

• Complete Right Hand Rules and Lenz's Law, practice #2

• Quiz on Friday over magnetism notes, right hand rules, and Lenz's Law.

• Sign up for flex to fix instruments.  RB PS, JG, LC LM, PI JG MB, JB, PG PW JD, HW, YN JB, EW JW TE,

Class 72.5 

Warm-Up :    The permanent magnet of the pickup on the right magnetizes the nearby section of steel string.  This string is currently moving upward as it vibrates near the pickup.

1.  What is the direction of the string's magnetic field?

2.  Is the flux from that field increasing or decreasing through the pickup coil?

3.  Through which wire is current flowing toward the amplifier. 

4.  Assuming that current travels straight through the amplifier on its way to the speaker, is the speaker cone currently being pulled toward the speaker magnet, or is it being pushed away from the speaker magnet?

Today: 

1. make a simple motor, like this one.  You will be provided with a magnet like the one in the picture, a D.C. power source, alligator clips, paper clips, wood or cardboard, and 1-2 meters of 24 gauge enameled magnet wire.  To be complete, your motor must run for at least 20 seconds on its own.  You may give it a push to get it started.
2. Make a speaker using 2m of 28gauge enameled wire, a few disk magnets, an audio jack with alligator clips, paper.   You will also need glue and/or tape.  Here's what mine looked like before I snipped off too much of the air pushing surface ("cone") .  Here are the directions. 

Homework:  Complete the rest of Right Hand Rule and Lenz's Law practice

Class 72 

Warm-Up :    Lenz's Law says that an induced current acts to keep magnetic flux constant. The hyperlinked diagram on the right illustrates applications of this law. According to Lenz's Law, when the coil is rotated as shown in the generator below, through which wire will current enter the bulb?

Today: 

1. In-class practice with RHRs and Lenz's Law.
2. After you finish your buzzer, disassemble it and put the wire back on a piece of cardboard.
3. make a simple motor, like this one.  You will be provided with a magnet like the one in the picture, a D.C. power source, alligator clips, paper clips, wood or cardboard, and 1-2 meters of 24 gauge enameled magnet wire.  To be complete, your motor must run for at least 20 seconds on its own.  You may give it a push to get it started.
4. Make a speaker using 2m of 28gauge enameled wire, a few disk magnets, an audio jack with alligator clips, paper.   You will also need glue and/or tape.  Here's what mine looked like before I snipped off too much of the air pushing surface ("cone")

Homework:  Complete 1-19 of Right Hand Rule and Lenz's Law practice  pdf version

Class 71.5 

Warm-Up :  

1.  Based on the direction of current flow, in which direction are the speaker cone and voice coil being pushed (or pulled) by the permanent magnet?

2.  To make a simple motor, should you sand one side or both sides of each end of your magnet wire?

Today: 

1. Look at tests
2. Finish your buzzer; build a motor.
3. make a simple motor, like this one.  You will be provided with a magnet like the one in the picture, a D.C. power source, alligator clips, paper clips, wood or cardboard, and 1-2 meters of 24 gauge enameled magnet wire.  To be complete, your motor must run for at least 20 seconds on its own.  You may give it a push to get it started.

Homework:  None

Warm-Up :   None

Today: 

1. Test today
2. Wednesday -- finish your buzzer; build a motor.

Homework:  Tonight's homework -- Use the web to learn out how to make a simple motor, like this one.  Make sure that you understand how it works.  Here's one video.  You will be provided with a magnet like the one in the picture, a D.C. power source, alligator clips, paper clips, wood or cardboard, and enameled magnet wire.

Class 70.5 

Warm-Up :  

A standard car horn is essentially a solenoid buzzer. 

1.  Which color (red or black) represents a complete circuit?

2.  Where is the solenoid?

3.  What makes this louder than the buzzer you have been working on?

4.  Why does the bottom diagram show two horns? Horn intervals

Today: 

1. Questions about tomorrow's test?
2. Magnetism Notes
3. Wednesday -- finish your buzzer; build a motor.

Homework:  Due on Wednesday -- Use the web to learn out how to make a simple motor, like this one.  Make sure that you understand how it works.  Here's one video.  You will be provided with a magnet like the one in the picture, a D.C. power source, alligator clips, paper clips, wood or cardboard, and enameled magnet wire.

Class 70 

Warm-Up:  

The left and right top diagrams on the right show magnetic field lines and the a right hand rule, respectively.  If you grab a current-carrying wire and point your right thumb in the direction of current, as shown, your fingers will point in the direction of the magnetic field.

1.  The third diagram shows a solenoid.  What is the difference between the words solenoid and electromagnet?

2.  In the third diagram, which end of the magnetized iron nail is north -- once the switch is closed?

3. Why is the north pole of a magnet called the "north" pole?

4.  How does a solenoid work in an electrical relay?

Today: 

1. Check for buzzer sketches
2. Magnetism Notes
3. Make a solenoid buzzer.
   1. Wood, nails, hot glue/glue guns, duct tape, enameled wire, sandpaper, saw, strips of magnetizable steel (approx 0.5" wide, 3" long), and a D.C. power source. 
   2. With those materials, you will have to make a working solenoid buzzer -- in groups of 2.  You may cut, glue, or tape things, but you will not be allowed to nail or drill.  Nailing and drilling are not necessary.

Homework:  None

Class 69.5 

Warm-Up :  

1.  What's wrong with this diagram?

2.  Why is the north pole of a magnet called the "north" pole?

Today: 

1. 7/8  Check/review homework -- problems in Practice Test:  Chapter 20-21.  Solutions
2. Mr. P's 4 minute drill Solutions
3. Draw buzzer designs

• Mr. Pennington's test review sheet (doesn't include Kirchoff's Laws)
• Interesting Link:  Electricity FAQs
• Magnetism Notes
• rhrs

Homework: 

• Watch this instructional video showing how to make a solenoid buzzer.  Draw a sketch of a solenoid buzzer design that uses only the materials below:
  •  wood, nails, hot glue/glue guns, duct tape, enameled wire, sandpaper, saw, strips of magnetizable steel (approx 0.5" wide, 3" long), and a D.C. power source. 
  • With those materials, you will have to make a working solenoid buzzer -- in groups of 2.  You may cut, glue, or tape things, but you will not be allowed to nail or drill.  Nailing and drilling are not necessary.

Class 69 

Warm-Up :   A simple motor can be made by running current through an insulated coil of wire, which then behaves like a magnet and pushes or pulls other magnets, depending upon their polarity.

A generator does this in reverse.  When a magnet is pushed or pulled in proximity to a coil of wire, current is produced in the wire.

Do you suppose the magnetic guitar pickup (lower right) is a motor or is it a generator?

Today: 

1. Finish reviewing multiple choice practice test questions.
2. Check homework -- Complete the second problem in Kirchoff's Rules Practice #2 (last problem of the packet).  The preceeding problem is optional.  Solutions
3. Discuss circuit lab questions.
4. Mr. P's 4 minute drill Solutions
5. Complete the problems in Practice Test:  Chapter 20-21.  Solutions

• Mr. Pennington's test review sheet (doesn't include Kirchoff's Laws)
• Interesting Link:  Electricity FAQs
• rhrs

Homework: 

• Watch this instructional video showing how to make a solenoid buzzer.  Draw a sketch of a solenoid buzzer design that uses only the materials below:
  •  wood, nails, hot glue/glue guns, duct tape, enameled wire, sandpaper, saw, strips of magnetizable steel (approx 0.5" wide, 3" long), and a D.C. power source. 
  • With those materials, you will have to make a working solenoid buzzer -- in groups of 2.  You may cut, glue, or tape things, but you will not be allowed to nail or drill.  Nailing and drilling are not necessary.
• Test next Tuesday over chapters 20-21.
• A7/8 -- complete problems in Practice Test:  Chapter 20-21.  Solutions

Class 68.5

Warm-Up :  

Today: 

• Check/review homework: 
  • Complete the rest of the problems in Kirchoff's Rules 21.3 Notes and practice Solutions
• Complete the multiple choice in Practice Test:  Chapter 20-21.  Solutions
• Hand back and discuss circuit lab questions.
• The test will be this Friday.  There's plenty of time to prepare. :-)

Homework: 

• Complete the second problem in Kirchoff's Rules Practice #2 (last problem of the packet).  The preceeding problem is optional.  Solutions
• Test on Friday.

Class 68

Warm-Up :   When electric current flows through an electric motor, a force is produced, causing motion.  An electric motor forced into motion generates electric current.

I have three identical corded drills and one driver bit.  With no additional materials, how can we power two of the drills by plugging just one of them into the wall?

Today: 

• Collect circuit lab questions.  Hand back and discuss circuit lab questions.
• Kirchoff's Rules 21.3 Notes and practice Solutions
• Practice Test:  Chapter 20-21.  Solutions

Online Textbook Reading:  Chapter 20 -- Electric Current

Homework: 

• Complete the rest of the problems in Kirchoff's Rules 21.3 Notes and practice Solutions
• Complete the multiple choice in Practice Test:  Chapter 20-21.  Solutions

Class 67.5

Warm-Up :   

Imagine a 110V home circuit that powers two light bulbs, a 100W bulb and a 60W bulb. 

1. Is the circuit most likely a parallel circuit or a series circuit?  How do you know?

2.  Which bulb will burn brighter when they are both turned on?

3.  Through which bulb will more current flow?

4.  Which bulb has a higher resistance?

5.  Why do the bulbs use more power than the wires that carry current to the bulbs?

Today: 

• Finish lab.  Turn in one per group, with all of your names on it.  Labs will be graded loosely on correctness.  You will lose points for impossible answers, but not for slightly inaccurate measurements.
• 

Online Textbook Reading:  Chapter 20 -- Electric Current

Homework:  None

Class 67

Warm-Up :   Assuming that the wires on the right have zero resistance...

Today: 

• Check/review homework: "Circuit Reduction -- The Nine Companions"   Solutions
• Notes and Circuit lab (using multimeters and DC power supplies) -- keep voltages per bulb under 6V.  Filled-In Notes
• Labs will be graded loosely on correctness.  You will lose points for impossible answers, but not for slightly inaccurate measurements.
• 

Online Textbook Reading:  Chapter 20 -- Electric Current

Homework:  None

Warm-Up :   

Today: 

• Check/review homework: 
  • A 5/6 -- Problem 1 from Ch21 Equivalent Resistance Challenge Solutions
  • A 7/8 -- Problem 2 from Ch21 Equivalent Resistance Challenge Solutions
• Get  "Circuit Reduction -- The Nine Companions"   Solutions

Online Textbook Reading:  Chapter 20 -- Electric Current

Homework:  Finish "Circuit Reduction -- The Nine Companions"   Solutions

Class 66

Warm-Up :   Check out the active graphic DC Circuit Water Analogy at Hyperphysics.com.  According to the analogy...

1.  Voltage is like _____

2.  Resistance is like _____

3.  Current is like _____

Today: 

• Check/review homework:  20.2 -- Notes and Practice Practice Solutions
• Notes:  20.3, 20.4, 21.1  Filled-in notes
• Problem 1 from Ch21 Equivalent Resistance Challenge Solutions
• Tomorrow -- "Circuit Reduction -- The Nine Companions"   Solutions
• Thursday -- Circuit-Building Lab

Online Textbook Reading:  Chapter 20 -- Electric Current

Homework:  Problem 2 from Ch21 Equivalent Resistance Challenge Solutions

Class 65.5

Warm-Up :   The deceptively complicated case of the electrified pickle...

joule heating

Electric Arc

Arc lamp

Hyperphysics electric pickle info

Today: 

• Check/review homework:  Chapter 19.1 and 19.2, Notes and Practice  19.1 and 19.2 Solutions and Filled-in Notes
• New:  20.2 -- Notes and Practice Practice Solutions

Online Textbook Reading:  Chapter 20 -- Electric Current

Homework:  Complete practice in  20.2 -- Notes and Practice Practice Solutions

Class 65

Warm-Up :   The diagram on the right shows two examples of acceleration and energy conservation.

1. What are the units for PE_elec?

2. Where could you move the positive charge in order to increase its electrical potential energy?

3.  Electrical Potential (a.k.a. voltage) is the ratio electrical potential energy to charge.  What are the units of electrical potential?

4.  This analogy comparing PE_elec to PE_grav isn't perfect.  Can you identify a shortcoming?

Today: 

• I told someone I would add a point, and I forgot.  Whose was it?
• Take a look at the online textbook:  19.1  20.1
• Rest of the year (rough plan):
  • Current and Circuits
  • Spring Break
  • Waves and Sound
  • Optics
• Chapter 19.1 and 19.2, Notes and Practice  19.1 and 19.2 Solutions and Filled-in Notes

Online Textbook Reading: Chapter 19.1 -- Electrical Potential (Voltage)     Chapter 20 -- Electric Current

Homework:  Complete practice in Chapter 19.1 and 19.2, Notes and Practice  19.1 and 19.2 Solutions and Filled-in Notes

Class 64.5

Warm-Up :   

1. What can Tango and Cash teach us about electricity?

2.  If you had to choose between touching a suspicous wire with the back of your hand or your palm, which should you choose?  Why?

Today: 

• Return Tizzes

• New Unit:  Current and Circuits

  • Silly video -- "Brainacs" getting shocked by an electric fence. 
  • Can we simulate an electric fence with an electric dog collar?
  • Take a look at the online textbook:  19.1  20.1
• Rest of the year (rough plan):
  • Current and Circuits
  • Spring Break
  • Waves and Sound
  • Optics

Online Textbook Reading: Chapter 19.1 -- Electrical Potential (Voltage)     Chapter 20 -- Electric Current

Homework:  None

Warm-Up :   

None

Today: 

• Tiz

Homework:  None

Class 63.5

Warm-Up :   

1.  Why doesn't a bird on an uninsulated power line get shocked?

2.  Would a bird get shocked if it landed on a Van de Graaff generator?

3.  How can we test #2?

4.  Why shouldn't you try #1?

Today: 

• Turn-in test corrections for rotational motion test.

• Check/discuss 18.7-18.8 practice  18.7  Mr. P. Solutions 18.8 Mr. P. solutions Mr. S. Solutions

• Tomorrow's Quiz/test format -- subject to minor change:  15 multiple choice, 1 short answer, 6 problems (4 problems with electrostatics equations, 2 electrostatics applications problems involving kinematics and/or F=ma and/or w=mg.)

• Note card

Online Textbook Reading:  Chapter 18.7

Homework:  Study

Class 63

Warm-Up :   

1. What is a spark?

2. How does a plasma ball work? Breakdown voltages, relative to air. tesla coil

3.  How does a jacob's ladder work?

Today: 

• Check/discuss Electrostatics Practice Test (Mr Pennington's Old Test)  -- Answer Key

• "4 minute drill" and test review.  Drill solutions

• Quiz format -- subject to minor change:  15 multiple choice, 1 short answer, 6 problems.

• Work time:

  • Static Equilbrium and Applications Problems:  Work on 18.7-18.8 practice  18.7  Solutions 18.8 solutions

  • Note card

 

Online Textbook Reading:  Chapter 18.4 and 18.5

Homework:   Finish 18.7-18.8 practice  18.7  Solutions 18.8 solutions  Video solutions:  18.7, number 2  18.7-18.8 -- the rest

Class 62.5

Warm-Up :   

Suppose the neutral conductor in diagram A is placed in the electric field shown in diagram B.

1.  How will the charges that are currently shown on the conductor rearrange themselves?  Assume that both positive and negative charges can move equally well.

2.  How will the electric field lines rearrange themselves?

Answer

3. Diagram C shows two conductors with excess positive charges.  Why do the excess charges reside on the conductors' surfaces?  Why are the charges closer together near the pointy part of the rightmost conductor?  What implications does this have for Van de Graaff generator design?

Today: 

• Check/discuss

  • Electric Field Hockey

  • 18.4 Practice -- Electric Fields  18.4 Practice Solutions

  • Chapter 18.5 Practice -- skip #2  Pennington Ch 18.5 Practice Solutions  p. 13-17 of Stapleton chapter 18 solutions (a bit disorganized ).

• Notes: 18.7 -- Conductors and Fields in Static Equilibrium. Notes 18.7 Key

 

Online Textbook Reading:  Chapter 18.7 and 18.8

Homework:   Electrostatics Practice Test (Mr Pennington's Old Test)  -- Answer Key

Class 62

Warm-Up :   

How does a Van de Graaff Generator Work?

MIT video -- inducing dipoles with a VDG

Today: 

• Check/discuss 18.3 Notes and Practice  Solutions

•  Good explanation of how the classroom Van de Graaff Generator works -- but backward relative to our classroom VDG.

• Notes 18.4 (Electric Field) -18.5 (Electric Field Lines).  Filled in Notes:  18.4   18.5 

• Complete Electric Field Hockey simulation in Notes 18.4 (Electric Field) -18.5 (Electric Field Lines)

Online Textbook Reading:  Chapter 18.4 and 18.5

Homework:  

• 18.4 Practice -- Electric Fields  18.4 Practice Solutions

• Chapter 18.5 Practice -- skip #2  Pennington Ch 18.5 Practice Solutions  p. 13-17 of Stapleton chapter 18 solutions (a bit disorganized ).

Class 61.5

Warm-Up :   

The electrophorus is charged by rubbing a cat(fur) against the top of an insulating plate (I).  Then the conducting plate (C) is placed on top of the insulating plate and is touched by the physicist.  Assuming that the cat fur has a strong affinity for negative charge...

1.  What is the charge of the plate after it is touched by the scientist? 

2.  Explain how the conducting plate becomes charged.

3.  What is the ground in this demonstration?

Today: 

• Check/discuss

  • Practice -- 18.1 and 18.2 (Static Electricity & Charge, Conductors and Insulators)

    • 18.1 Solutions

    • 18.2 Solutions

• Balloons  John Travoltage

• Old key to Travoltage and Balloon/sweater Simulations

 

Ch 18.3: Coulomb's Law 18.3 Notes and Practice  Filled-in Notes

Online Textbook Reading:  Chapter 18.3

Homework:   Complete 1-5 in 18.3 Notes and Practice  Solutions

Class 61

Warm-Up :   

1.  If you rub a balloon on your head and then hold it next to your hair, your hair is attracted to the balloon.  Why?

2.  Your hair may also stand on end after being rubbed by a balloon.  Why?

3.  The balloon may stick to the wall or ceiling.  Why?

4.  This all works better in drier air.  Why?

5.  What events contributed to this gas station fire?

Today: 

• There will be no more instrument work time in class.  We will return to the instruments after the electricity units.

• Rotational motion quiz corrections due next Tuesday.

• Notes and Practice -- 18.1 and 18.2 (Static Electricity & Charge, Conductors and Insulators)  Filled-in Notes

  • Vsauce Video: We can't really touch anything

• Phet Simulations -- Complete questions: Balloons and John Travoltage

  • Links:  Balloons  John Travoltage

  • Old key to Travoltage and Balloon/sweater Simulations

The rest of the quarter: 

• Today -- Ch. 18.1 and 18.2:  Static Electricity and Charge; Conductors and Insulators
• Tuesday -- Ch 18.3: Coulomb's Law 18.3 Notes  18.3 Practice
• Wednesday -- Ch 18.4 and 18.5: Electric Fields and Field Lines
• Thursday --  18.7:  Conductors and Fields in Static Equilibrium
• Friday -- Conferences
• Monday -- Electrostatics Practice Test (Mr Pennington's Old Test)  -- Answer Key
• Tuesday -- "4 minute drill", Quiz review
• Wednesday -- Quiz
• Thursday -- Return Quizzes -- Corrections due by Tuesday
• Friday -- Last day of the quarter -- Begin Chapters 20-21 -- Current and Circuits

Online Textbook Reading:  Chapter 18.1 and 18.2

Homework:  

• Practice -- 18.1 and 18.2 (Static Electricity & Charge, Conductors and Insulators)

  • 18.1 Solutions

  • 18.2 Solutions

Class 60.5

Warm-Up :   

See example slide, on the right.

 Today: 

• Clean up:
  • Scrape and brush countertops
  • Clean out cabinets and store instruments in an organized manner.
• Finishing touches -- stringing, tuning
• Get a nice photo of your instrument and fill out a slide for your group.
  • A5/6 Slides
  • A7/8 Slides
• Sources for songs to play (easiest major keys are C and G; easy minor keys are Am and Em):
  • ukulele -- ukutabs.com
  • tuning in 5ths -- mandotabs.com

Online Textbook Reading:

Homework:  

Class 60

Warm-Up :   

1. What are some ways of tuning a string instrument?

2. What's a shim?

3. How do you know what key a song is in, based on chords?  How can you change the key? 

 Today: Last full work day.  Tomorrow we clean up and store the instruments in a careful, intentional manner.  Any additional work will need to be done during flex.

• I have new, laser cut bridges and nuts that should work for most instruments.  If the nut is too low, you may be able to raise it with a shim.
• Relative tuning method -- you won't know what key you're in, but if your instrument is well made, this should get it to sound in tune 
• Final Instructions
• Sources for songs to play (easiest major keys are C and G; easy minor keys are Am and Em):
  • ukulele -- ukutabs.com
  • tuning in 5ths -- mandotabs.com

Online Textbook Reading:

Homework:  

Class 59.5

Warm-Up :   

How do this bridge and nut need to be modified?

 Today: 

• There are more green tuners today.
  • Final Instructions

Online Textbook Reading: 

Homework:  

Warm-Up :   

Watch videos -- saddles, knobs, plastic tuners (easy green ones, black ones)

 Today: 

• Final steps, attaching the saddle, adding the string, tuning.
  • Final Instructions

Online Textbook Reading: 

Homework:  

Class 58.5

Warm-Up :   

How do pop rivets work?

 Today: 

• Final steps -- wrapping the fret wire, attaching the saddle, adding the string, tuning.
  • Day 6 Instructions

Online Textbook Reading: 

Homework:  

Class 58

Warm-Up :   

These pictures compare the fret "wire" that we will be using to standard fret wire.  We will wrap the fret wire.

Why does the fret wire need to be wrapped very tightly?

 Today: 

• Final steps -- wrapping the fret wire.  Attaching the saddle.
  • Today's Instructions

Online Textbook Reading: 

Homework:  

Class 57.5

Warm-Up :   

1. How do you load new sandpaper into this type of finishing sander?

2. What's the number 1 rule for prolonging the life of sandpaper in the finishing sander?

 Today: 

• Video -- how to swap sandpaper in the finishing sander
• Prepare a neck and fret board.  Label and store them with your names and a piece of tape.
  • Today's Instructions

Online Textbook Reading: 

Homework:  

Class 57

Warm-Up :   

What hazards are posed by a belt sander?

 Today: 

• Google search for Mrstapleton.com is acting funny.
• A5/6 ends at 12:49.  A7/8 starts at 1:23.
• Belt sander:  Use it for body edges, corners, and your peg box (video).
• New dust collector switch
• Video: Cleaning the belt sander
• Video: Laser Cutting the body
• Pre-made hole patterns: 
• Prepare a neck and fret board.  Label and store them with your names and a piece of tape.
  • Today's Instructions

Online Textbook Reading: 

Homework:  

Class 56.5

Warm-Up :   

What are the most important things to remember when you're using a scroll saw?

 Today: 

• Prepare a neck and fret board.  Label and store them with your names and a piece of tape.
  • Instructions
• Finish Notes: Wave and Music theory relating to fret calculations -- and fret practice -- shorten to focus only on fundamental  Filled-in notes
  • Division of the octave
    • Online Piano Keyboard
  • Calculating vibrating string length (distance from nut to frets).
• Mechanical Waves Links

Online Textbook Reading: 

Homework:   Email this to Mr. Stapleton...  Modify this fret calculation template to create a spreadsheet that will calculate fret positions for any length string.  You will use this spreadsheet for calculating your instrument's fret positions.  Answers for a 33cm bridge-to-nut distance @440Hz.  Video showing how to do this.

Class 56

Warm-Up :   The frequency of a wave describes number crests or troughs that pass a particular point in a given amount of time (a.k.a. cycles per second).  The units are Hertz (Hz).

1.  What is the frequency of the wave pattern on the right?

2.  If the distance between two successive crests (i.e. wavelength) is 4m, what is the speed of the waves on the right?

3.  What is the formula for wave speed, in terms of frequency and wavelength?

 Today: 

• Assemble/glue instrument bodies and peg boxes.
  • Instructions
• If you want help with your sound hole design, come to my flex tomorrow.
• Notes: Wave and Music theory relating to fret calculations -- and fret practice -- shorten to focus only on fundamental  Filled-in notes
  • Wave interference and standing waves
1. Standing wave simulation
2. Make interfering and standing waves, using a shlinky
3. Standing wave video
• Division of the octave
  • Online Piano Keyboard
• Calculating vibrating string length (distance from nut to frets).
• Mechanical Waves Links

Online Textbook Reading: 

Homework:   None

Class 5

Warm-Up :   Suppose you need to want to build a camp fire.  You have plenty of dry wood, but it's all big limbs that are too long to be manageable and too thick to break over your knee.  Without using a saw or an axe, what's the best way to divide the wood into smaller pieces?  Can you describe the proper technique?  One solution.

 Today: 

• Return tests
• Assemble instrument bodies.  Glue, tape, and label with your names.

Online Textbook Reading: 

Homework:   None

Warm-Up :   No warm-up

 Today: 

• Test
• Tomorrow -- return tests and assemble instrument bodies.

Online Textbook Reading: 

Homework:   None

Class 54.5

Warm-Up :   A quadcopter has four propellers that usually alternate in their directions of rotation.

 Today: 

• Try the device?
• Problems from Rotational Motion Test Review #1  Solutions to Pennington Test Review
• Test Practice Materials:

  • Rotational Motion Test Review #1 

    • Solutions to Test Review #1

    • Problem solution video

    • Multiple Choice Solution Video

  • Rotational Motion Practice Test # 2, Rotational Motion 
    • Solutions to Rotational Motion Practice Test #2. 
    • If you don't understand the solutions, watch the videos below. 
      • Multiple Choice
      • Problem 1
      • Problem 2
      • Problem 3
      • Problem 4
      • Problem 5
      • Problem 6

       

Online Textbook Reading:  Chapter 10

Homework:   Test tomorrow

Class 54

Warm-Up :   

1. How do falling cats always manage to land on their feet?
2. Why do falling people flail their arms around?

 Today: 

• About half of you filled out the form.  I doubled the materials that it looked like I was going to need, based on the form.  If you submitted the form by 8:00 this morning, you're guaranteed to get what you asked for. 
• If you want to have a scale length (nut to bridge) that is longer than about 15 inches, please let me know your scale length by email.
• Check/review homework: Multiple choice from Rotational Motion Test Review #1  Solutions to Pennington Test Review
• Test Practice Materials:

  • Rotational Motion Test Review #1  Solutions to Pennington Test Review Problem solution video Multiple Choice Solution Video

  • Rotational Motion Practice Test # 2, Rotational Motion  Solutions to Rotational Motion Practice Test #2.  If you don't understand the solutions, watch the videos below. 
    • Multiple Choice
    • Problem 1
    • Problem 2
    • Problem 3
    • Problem 4
    • Problem 5
    • Problem 6

     

Online Textbook Reading:  Chapter 10

Homework:  

• Problems from Rotational Motion Test Review #1  Solutions to Pennington Test Review

• If you want extra practice, work on Rotational Motion Practice Test # 2, Rotational Motion  Solutions to Rotational Motion Practice Test #2.

Class 53.5

Warm-Up :   In the picture on the right, the wheel is spinning, and the guy is sitting motionless on a chair that rotates freely.  What will happen when he flips the wheel over so that it rotates in the opposite direction?

 Today: 

• Fill out this form (one per group), relating to who is in your group and what type of instrument you hope to make.
• Check/review homework:

  • # 1,2,4 and 5 from  Chapter 10.4 -- Rotational Kinetic Energy Notes and Practice  Practice Key

  • #2 and 4 from 10.5 Angular Momentum Notes and Practice Practice Key

• Rotational Motion Test Review #1  Solutions to Pennington Test Review Problem solution video Multiple Choice Solution Video

• Rotational Motion Practice Test # 2, Rotational Motion  Solutions to Rotational Motion Practice Test #2.  If you don't understand the solutions, watch the videos below. 
  • Multiple Choice
  • Problem 1
  • Problem 2
  • Problem 3
  • Problem 4
  • Problem 5
  • Problem 6

   

Online Textbook Reading: 

Homework:  

Multiple choice from Rotational Motion Test Review #1  Solutions to Pennington Test Review

Class 53

Warm-Up :   Explain how this jar lid closure works, in terms of Net Torque -- especially T_net=Frsinθ.

You might also consider F=kx. 

 Today: 

• How many groups want to make a 6-string instrument? -- more work.  Tuning will be more difficult. 
• Example top.  Hole took about 10 seconds.  Engraving took 21 minutes.  Don't make this mistake
• If you want help with your instrument top, come to my flex.
• Chapter 10.4 -- Rotational Kinetic Energy Notes and Practice -- Notes Key  --  Practice Key
• 10.5 Angular Momentum Notes and Practice -- Notes Key -- Practice Key -- Solution to #1
• Test next Thursday over rotational motion

Online Textbook Reading: 

Homework:  

• Complete the rotational kinetic energy and angular momentum practice problems

  • # 1,2,4 and 5 from  Chapter 10.4 -- Rotational Kinetic Energy Notes and Practice -- Notes Key  -- Practice Key

  • #2 and 4 from 10.5 Angular Momentum Notes and Practice -- Notes Key -- Practice Key

   

Warm-Up :  

 Today: 

• Return quizzes.  Corrections are due before break.
• Design sound holes.  Click this link for instructions and tips.
• Example instrument file

Online Textbook Reading: 

Homework:  

• None.  Get a good sleep, so you're ready for rotational KE and rotational momentum tomorrow.

Warm-Up :    A sphere, a cylinder, a ring, and a frictionless box are released from rest at the top of ramp.  Their masses and heights are identical.

1.  Rank the objects according to their arrival times at the bottom of the ramp.

2.  Suppose the bottom end of the ramp is frictionless, and when they reach the bottom, the objects hit a vertical, frictionless wall.  What motions, if any, would continue after impact?

3.  How this event be different if the objects varied in mass and/or height?

4.  The round objects are affected by friction.  Would the result be different in a totally frictionless situation?  Explain.

 Today: 

• Return quizzes.  Corrections are due before break.
• Check/review homework:   Chapt 10.2 and 10.3 -- Kinematics and Dynamics of Rotation Practice -- Key
• Chapter 10.4 -- Notes and Practice -- Rotational Kinetic Energy Practice --Notes Key -- Practice Key

Online Textbook Reading: 

Homework:  

• Sketch a sound hole design (due on Wednesday).

Class 51

Warm-Up : 

1.  Where does a compound bow store most of its energy?

2.  What purpose(s) do the pulleys of a compound bow serve?

 Today: 

• Survey Responses
• Quiz finishers?
• New concepts:
  • Chapt 10.2 -- Kinematics of Rotation Notes -- Key
  • Chapt 10.3 Rotational Dnamics Notes Key
  • Chapt 10.2 and 10.3 -- Kinematics and Dynamics of Rotation Practice -- Key
• Design an instrument sound hole -- or sound holes.  You can cut through or engrave.  Engraving (burning images) takes a lot of time.    If you're planning to electrify your instrument (extra work, probably some out of class), you should account for the position of your pickup.
• On Wednesday, you will be creating CAD files of your design.

   

Online Textbook Reading: 

Homework:  

•  Chapt 10.2 and 10.3 -- Kinematics and Dynamics of Rotation Practice -- Key

• Sketch a sound hole design (due on Wednesday).

Class 50.5

Warm-Up : 

1. What does a differential do?

2.  How does a differential work?

 Today: 

• Return Quiz and other papers

• Check/review Angular Acceleration Practice -- Key

• New concepts:
  • Chapt 10.2 -- Kinematics of Rotation Notes -- Key
  • Chapt 10.2 -- Kinematics of Rotation Practice -- Key

   

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework:  

•  None

Class 50

Warm-Up :  What do you notice about this comic situation portrayed in the Stall Street Journal?

 Today: 

• Quiz

• A5/6 -- Finish Acceleration Notes

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework:  

•  Angular Acceleration Practice -- Key

Class 49.5

Warm-Up :  Suppose you need to screw an abutment into a fixture that is implanted in someone's jaw.  How can you make sure that you screw it in just tight enough, but not too tight?

 Today: 

• Check/review homework Torque Practice (Pennington)   Torque Practice Solutions

• Angular Acceleration Notes -- Key
• Angular Acceleration Practice -- Key

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework:  

• Test tomorrow over impulse and momentum. 

Class 49

Warm-Up :  In the rotational (angular) motion unit, we will be using new units that are analogous to our current, linear units.  You will need to be able to work in radians.

 Today: 

• Linear Momentum Practice Quiz (last year's quiz, mostly)  Solutions

• Return impulse lab.

• Torque

• Torque Notes (Pennington)    Torque Notes Key
• Torque Practice (Pennington)   Torque Practice Solutions

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework:   Torque Practice (Pennington)   Torque Practice Solutions

Warm-Up : 

 Today: 

• Check/review # 8,9,10,11,13,14 in Coefficient of Restitution, Plus Various Momentum Problems Solutions (except 13-14)  Solutions to 13 and 14 

• Return impulse lab.

• Discuss Egg Bungee Assignment -- Most groups are not providing a proper answer to the question.  Grading is out of 4 points; 1 point each for: visible and correct axes labels, visible axes numbers, correct calculations, correct answer to the question.   You can resubmit a screen shot for full credit.  The assignment is required.

• Linear Momentum Practice Quiz (last year's quiz, mostly)

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework:   Linear Momentum Practice Quiz (last year's quiz, mostly)  Solutions

Class 48

Warm-Up : 

 Today: 

• Check/review Mr. Pennington's Old Momentum Test.  Answers/Solutions.

• Turn in impulse lab -- Discuss data and answers

• Video of impulse measurement

• Coefficient of Restitution, Plus Various Momentum Problems  Do first example and number 7.  Talk about #13.

• Group bungee problem is due today.  See details from last class.

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework:  Complete # 8,9,10,11,13,14 in Coefficient of Restitution, Plus Various Momentum Problems Solutions (except 13-14)  Solutions to 13 and 14 

Warm-Up : 

 Today: 

• Complete Mr. Pennington's Old Momentum Test.  Answers/Solutions.

• Finish the group homework (below)

• Finish the impulse lab from yesterday.

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework: 

• Individual:  (handed out yesterday) Mr. Pennington's Old Momentum Test.  Answers/Solutions.

• Due tomorrow (1 per group):  Using these data, calculate the final bungee distance from the floor for a 300g bungee jumper that free-falls 0.5m.  Calculate an answer and create a screen shot of your graphical solution.  Make sure that your screen shot clearly shows the axes labels and numbers, and that it clearly shows the two curves intersecting at your answer.  Submit your work by emailing me two things -- 1) your answer  2) the screen shot

• Due tomorrow (1 per group):  Impulse Lab (from yesterday).

Class 47

Warm-Up : 

Today: 

• Check/review homework  Notes and Ballistic Pendulums:  8.3 -- Conservation of Momentum and 8.4 -- Elastic and Inelastic Collisions, find the initial velocity of the projectile in example launch 2.  Spreadsheet Solution

• Impulse Notes and Practice -- Old Notes Key, Old Practice Key

• Complete Lab -- Collision and Impulse and turn in -- one sheet per group of up to 3 students.

• Get work for tomorrow -- Mr. Pennington's momentum quiz.

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework: 

• Due on Friday (1 per group):  Using these data, calculate the final bungee distance from the floor for a 300g bungee jumper that free-falls 0.5m.  Calculate an answer and create a screen shot of your graphical solution.  Make sure that your screen shot clearly shows the axes labels and numbers, and that it clearly shows the two curves intersecting at your answer.  Submit your work by emailing me two things -- 1) your answer  2) the screen shot

Warm-Up : 

Today: 

• Check/review homework  Notes and Practice:  Linear Momentum and Force   Problems Key

• Notes and Ballistic Pendulums:  8.3 -- Conservation of Momentum and 8.4 -- Elastic and Inelastic Collisions  Answer Key

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework: 

• Due tomorrow:  Using the data from Notes and Ballistic Pendulums:  8.3 -- Conservation of Momentum and 8.4 -- Elastic and Inelastic Collisions, find the initial velocity of the projectile in example launch 2.

• Due on Friday (1 per group):  Using these data, calculate the final bungee distance from the floor for a 300g bungee jumper that free-falls 0.5m.  Calculate an answer and create a screen shot of your graphical solution.  Make sure that your screen shot clearly shows the axes labels and numbers, and that it clearly shows the two curves intersecting at your answer.  Submit your work by emailing me two things -- 1) your answer  2) the screen shot

Class 46

Warm-Up : 

Today: 

• Return bungee homework (due last class) -- discuss answer and solution.

• Get data to test your group's bungee drop calculating abilities.  See homework assignment, below.

• Notes and Practice:  Linear Momentum and Force  Notes Key Problems Key

• Collect data relating to ballistic pendulum swing height and projectile mass.  Ceate a projectile with a mass between 10g and 20g that will travel as fast as possible when shot from a 1/2" potato launcher.

  • Record your swing height and projectile mass.

  • Notes and Ballistic Pendulums:  8.3 -- Conservation of Momentum and 8.4 -- Elastic and Inelastic Collisions  Answer Key

• Clean up, work on homework for tomorrow or Wednesday.

Online Textbook Reading:  Chapter 8:  Linear Momentum and Collisions

Homework: 

• Due tomorrow:  Notes and Practice:  Linear Momentum and Force  Notes Key Problems Key

• Due on Wednesday (1 per group):  Using these data, calculate the final bungee distance from the floor for a 300g bungee jumper that free-falls 0.5m.  Calculate an answer and create a screen shot of your graphical solution.  Make sure that your screen shot clearly shows the axes labels and numbers, and that it clearly shows the two curves intersecting at your answer.  Submit your work by emailing me two things -- 1) your answer  2) the screen shot

Warm-Up :  When you're ready to drop your egg, tell me your board heights, and I will position the board for you.

Today: 

• Turn in your homework to the wire basket. The answer should be around 3.26m.

• Get an egg.  Measure its mass, and prepare your bungee. There are already weights attached to the harnesses.  Leave them attached.  Current masses of the harnesses, without eggs, are:

  • #1 -- 223.9g

  • #2 -- 223.6g

  • #3 -- 222.3g

Homework:  None

Class 45

Warm-Up : 

1.  How can you attach weights to the egg bungee jump harness in the picture?

2.  How do you attach the bungee to the egg harness?

Today: 

• Check homework

• How to complete tonight's homework.

• Egg Bungee Jump Activity:

  • If necessary, finish collecting data.  No bungee jumping is allowed.  You may only collect force data.

  • Modify your homework spreadsheet to work for your bungee.  At some point, you will be given a "free-fall" distance, an egg, a harness mass, and an added mass.  You can use these values to determine a stretch distance and make a plan regarding your board position. 

  • You will get two drops to get your egg as close as possible to a board that you position beneath the egg.  You must declare your board height, in writing, for both drops before making the first drop.  If your egg does not break on the first drop, you may drop it again at your second board height.

  • The egg that comes closest to the board without breaking wins.

Homework:  Complete problem #2 in Bungee Jumper Problems solution to part 1

Warm-Up :  An egg with a mass of 0.1kg is dropped from a height of 3m.  When the egg reaches a height of 2.5m, it begins stretching a spring with k = 1.5N/m.  At what height will it stop stretching the spring? Answer

Today: 

• Return papers. 

• Look at exams and return.  Check point calculation errors.

  • Last Year's Classes' Raw Scores:

    • Multiple Choice:  15.8, 16.1 -- Ave 16 (I got rid of one hard question, and substituted an easy one)

    • Problems: 64.6, 61.2  -- Ave 62.9

  • This Year's Raw Scores:

    • Multiple Choice: 16.5, 16.5 -- Ave 16.5

    • Problems: 59.9, 65.2 -- Ave 62.6

• Egg Bungee Jump Activity:

  • If necessary, finish collecting data.

  • Add two new columns to your data table

    • One column showing the new work done during the past stretching interval

    • One column showing the total amount of work done by stretching the bungee to each distance.

Homework:  Create a graph to find the stopping point of the bungee jumper.  Complete this template.  Write down your final answer on paper.

Class 43.5

Warm-Up :  More Yo-Yo

1. The graphs on the right correspond to one down-up cycle of a yo-yo.  How can the yo-yo speed graph be correct if the velocity graph is wrong?

2.  When the yo-yo stalls at the lowest point in its path, what kind of PE and KE does it have?

3.  Given that a yo-yo is not a 100% efficient device, how does the operator make it come all of the way back to the top?  How does this work, in terms of KE and PE? 

4.  Is there a way to get the yo-yo to return to the hand without adding any extra KE to the yo-yo?

Today: 

• Return quiz -- turn in corrections ASAP, at least before grades are due.

• Time for questions.

• Review Stuff

  • Semester 1 Formulas

  • Midterm Study Guide

  • Chase Packets

• Kinematics (solutions)

• Forces (solutions)

• Circles and Gravity (solutions)

• Energy (solutions)

• Stapleton packets

  • Kinematics

  • Newton's Laws

  • Circles and Gravitation

  • Energy -- our quiz should be good review.

Homework: 

• Midterm

Warm-Up : 

None -- start quiz immediately

Today: 

• Practice Quiz (solutions)-- similar to tomorrow's quiz

• Review Stuff

  • Semester 1 Formulas

  • Midterm Study Guide

  • Chase Packets

• Kinematics (solutions)

• Forces (solutions)

• Circles and Gravity (solutions)

• Energy (solutions)

• Stapleton packets

  • Kinematics

  • Newton's Laws

  • Circles and Gravitation

  • Energy -- our quiz should be good review.

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Review for the midterm.  Next class is your last good chance to ask questions, so be as prepared for that as you can be.

• Midterm reviews are due on exam day.

Class 42

Warm-Up : 

1.  How does this yo-yo work? What do the springs and steel balls do?

2.  Suppose a 100% efficient yo-yo falls down and comes up through one cycle.  Would either (or do both) of these graphs realistically portray its motion?  Explain.  

3.  What would graphs of KE and PE look like?

Today: 

• Practice Quiz (solutions)-- similar to tomorrow's quiz

• Review Stuff

  • Semester 1 Formulas

  • Midterm Study Guide

  • Chase Packets

• Kinematics (solutions)

• Forces (solutions)

• Circles and Gravity (solutions)

• Energy (solutions)

• Stapleton packets

  • Kinematics

  • Newton's Laws

  • Circles and Gravitation

  • Energy -- our quiz should be good review.

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Quiz tomorrow.  Tomorrow is a split block, so be ready to start immediately.

Warm-Up : 

1.  When does each of these energy conservation equations apply to the diagram below?

2.  Would your answer change if this were a completely frictionless environment?

Today: 

• Check/review (7-11) of the energy portion of the midterm review packets.  Solutions

• Review Stuff

  • Semester 1 Formulas

  • Midterm Study Guide

  • Chase Packets

• Kinematics (solutions)

• Forces (solutions)

• Circles and Gravity (solutions)

• Energy (solutions)

• Stapleton packets

  • Kinematics

  • Newton's Laws

  • Circles and Gravitation

  • Energy -- our quiz should be good review.

• A5/6 -- Midterm Review Work Time

• A7/8 ?

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• None

Class 40.5

Warm-Up : 

Both graphs represent work that was done over a 3m distance.  Estimate the work done in each case.

Today: 

• The Work/Energy quiz will be on Thursday.  There will be problems only; no multiple choice.  No kinematics formulas will be necessary. There will be one problem involving a roller coaster, a spring, and friction.

• Check/review Bone on bone hill (with springs) problem   Solutions

• Semester 1 Formulas

• Egg Bungee Jump Activity:

  • If necessary, finish collecting data.

  • Add two new columns to your data table

    • One column showing the new work done during the past stretching interval

    • One column showing the total amount of work done by stretching the bungee to each distance.

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Complete the rest (7-11) of the energy portion of the midterm review packets.(solutions)

Class 40

Warm-Up : 

1.  Is tension the same in all parts of the slinky on the right?

2.  What happens when you suspend a slinky (as shown in the photo on the right) and then drop it?

3.  Why?

Slinky drop

Slinky drop answer

1st Video

Slinky drop with tennis ball

Supersized Slinky

Today: 

• Test corrections are due today.

• Check/review 1-6 of Energy (solutions)

• Bone on bone hill (with springs) problem   Solutions

• Semester 1 Formulas

• Egg Bungee Jump Activity:

  • In groups of 2 or 3, collect Egg Bungee Jump Contest Data  -- Create a table of forces and stretch distances for your bungee.  Return your bungee.

  1. Write down your bungee number

  2. One column for hanging mass

  3. One column for force applied by hanging mass (i.e. weight)

  4. One column for distance stretched (x)

  • Add two new columns to your data table

    • One column showing the new work done during the past stretching interval

    •  One column showing the total amount of work done by stretching the bungee to each distance.

  • Create a graph showing the total amount of work done by stretching the bungee to any distance, up to the distance at which the bungee reaches the floor.  The format should be work vs stretch distance.  Work goes on the y axis; stretch distance on the x axis. 

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Bone on bone hill (with springs) problem   Solutions

Class 39.5

Warm-Up : 

If we tighten a rope between the end of the board and the digital scale, the digital scale will tell us the tension in the rope.  How tight do you think we can get the rope?  What's the best way to tighten a rope if you want to be able to untie it later?

Today: 

• Check/review Spring practice problem  Solutions -- see my YouTube channel for video solutions

• Pass out Midterm Review Packets -- Due next Friday.  Will count for up to 20% of your exam grade -- if you complete them and show your work.

  • Kinematics (solutions)

  • Forces (solutions)

  • Circles and Gravity (solutions)

  • Energy (solutions)

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Complete 1-6 of the energy portion of the midterm review packets.

• Test corrections due tomorrow

Warm-Up : 

For an ideal spring, the applied force is directly proportional to the stretch distance*.

The spring constant, k, is the ratio of force to stretch distance.  The units we will use for k are N/m. 

Suppose a screen door spring has a spring constant k = 40N/m.

1.  What is the tension in the spring when it is stretched 1m?

2.  What is the tension in the spring when it is stretched 20cm?

3.  If we use x for a spring's stretch displacement, derive a formula for the force exerted by the spring. F_spring = ?

3.  How much work is required to stretch the spring from a stretch distance of 0m to a stretch distance of 1m?

4.  How much work is required to stretch a spring from 0 to x meters if its spring constant is k?  In other words, derive the formula for PE_spring.

_{*In the case of a compression spring, x is the compression distance.}

Today: 

• Midterm Review Packets (all except work and energy).  I am not printing these until Friday.  I may make some changes between now and then.

  • Kinematics

  • Newton's Laws

  • Circles and Gravitation

  • Semester 1 Formulas

• Together -- Complete 1-3 in  "Spring Energy and Review Problems"  (solutions)

• Spring practice problem  Solutions

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Spring practice problem  Solutions -- see my YouTube channel for video solutions

Class 3

Warm-Up :  In order to deliver his presents on time, what forces, accelerations, and other physical obstacles does Santa encounter?

Today: 

• Trebuchet results from 7/8

• Short Video:  Santa Claus from an Engineer's Perspective

• Midterm Review Packets (all except work and energy)

  • Kinematics

  • Newton's Laws

  • Circles and Gravitation

• Learn to secure a load with a bowline and a Trucker's Hitch (with a slippery half hitch and a slip knot)
  • Bowline:        Slippery Half Hitch:       
  • Slip knot:       

•  

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• None

Class 3

Warm-Up : 

A trebuchet's projectile is launched as its counterweight falls, thereby turning PE into KE and accelerating the projectile.

1.  Does the projectile do work on the counterweight or vice-versa?  Or does each do work on the other?  Explain.

2.  At which end of the trebuchet arm does the work being done look like this ⇒ Fd   ?

3.  Record the current temperature, air pressure, and relative humidity.

Today: 

• Launch trebuchet -- collect data to calculate efficiency and drag coefficient.

• Cantaloupe Measurements:

  • A5/6 -- Average diameter = 0.152m;  Mass = 2.00kg

  • A7/8 -- Average diameter = 0.156m;  Mass = 1.98kg

• Finish reviewing homework  -- #4-10 in "Spring Energy and Review Problems"  (solutions)

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• None

Class 37.5

Warm-Up : 

The pictures on the right all show simple machines.  Simple machines allow the same work to be done with more convenient combinations of force and distance. 

1.  Identify the task (work) in each picture.

2.  For each picture, identify the machine (s).

3.  For each machine, tell how the machine alters the distance over which force must be applied by the human using the machine.

4.  How does the machine alter the force that the human must apply?

5.  Which machine is fundamentally different from the other 3? Why?

Today: 

• For Newton's Laws in 2-D quiz corrections, show your work on separate paper, but write your new answers next to your old answers, using a different colored pen.

• Check/review homework  -- #4-10 in "Spring Energy and Review Problems"  (solutions)

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• None

Class 37

Warm Up: 

1.  What does the "sisyphus train" do?

2.  How did it get that nickname?

3.  In the context of physics energy problems, some forces are called conservative, and others are referred to as non-conservative.  Can you guess the difference between the two?

Today: 

• Check/review homework #5

• Finish notes -- Energy and Work.  Answers/solutions

• Complete and discuss:

  • Problem #6 in  Energy and Work. 

  •  ?Problems in Practice Quiz  Excel Solutions

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Complete #4-10 in "Spring Energy and Review Problems"  (solutions)

Class 36.5

Warm Up: 

1.  What is the difference between kinetic energy and potential energy?

2.  A 1kg ball travels directly upward.  Its initial KE = 8J.  How much kinetic energy will it have when it reaches its highest point? (ignore air resistance)

3.  How much potential energy (PE) will it have when it reaches its highest point?

4.  As the ball rises, what is doing work on what?

5.  What is the formula for gravitational PE, and where does it come from?

Today: 

• Return Tezts

• Watch H positive?

• ?Work on homework

• ?Notes on Conservation of Energy with and without Nonconservative Forces -- Energy and Work.  Answers/solutions

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework:  Complete Problem #5 in  Energy and Work.  Answers/solutions

Warm Up: 

None

Today: 

• Test

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework:  None

Class 35.5

Warm Up: 

1. What is the purpose of a centrifuge?

2.  Can you use a bathroom scale to find the weight of the Earth?

Today: 

• Check/review homework:  Problems 1-4 from Work and Energy.  Answers/solutions

• What to expect from the test -- Test review checklist

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Little test/big quiz tomorrow. 

Class 35

Warm Up: 

1. How are g-forces dangerous to pilots?

2.  In this video, a driver attempts to traverse a large loop-the-loop.  In order to safely complete his mission, how many g's do you suppose the driver needs to tolerate?

Today: 

• Any more questions about the homework that was assigned two days ago? -- More practice-- Circular Motion, Gravitation, Kepler Solutions

• New Unit Notes:  Work and Energy.  Answers/solutions

Online Textbook (OpenStax) Reading: 

• Chapter 7 Introduction

• 7.1  Scientific Definition of Work

• 7.2  Work-Energy Theorem

• 7.3  Gravitational Potential Energy 

• Chapter 7.4 -- Potential Energy and Conservative Forces (spring energy)

Homework: 

• Problems 1-4 from Work and Energy.  Answers/solutions

Class 34.5

Warm Up: 

1.  Approximately how fast is the jogger in this video moving, relative to the center of rotation?

2.  If the jogger turned around and jogged the other way, would he feel any different?

3.  Identify a centripetal force and a centrifugal force in this video.

Today: 

• Check/review homework -- 1 hour of work on More practice-- Circular Motion, Gravitation, Kepler Solutions

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework: 

• Finish  More practice-- Circular Motion, Gravitation, Kepler Solutions

• Little test/big quiz on Friday.  The test will cover circular motion, gravitation, and Kepler's Laws.

Class 34

Warm Up: 

1.  Does it take longer for the satellite to travel from point A to point B or from point C to point D? How do you know?

2.

3.  What is a geosynchronous satellite?

4.  What's the difference between a geosynchronous orbit and a geostationary orbit?

5.  What is a space elevator?

Today: 

• Check/review homework -- problems from Practice -- Mr. Pennington's 2015 test.  Solutions (although #5 and #7 are in radians).  Video tips on solving the problems, including 5 and 7 in linear terms.

• Get --  More practice-- Circular Motion, Gravitation, Kepler Solutions

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework: 

• Spend at least an hour on this.  You can stop after an hour, even if you're not done. --  More practice-- Circular Motion, Gravitation, Kepler Solutions

• Little test/big quiz on Friday.  The test will cover circular motion, gravitation, and Kepler's Laws.

Class 33.5

Warm Up: 

From 2016-2017 EPS 200...

The Sun, Earth, and Moon are continually spaghettifying one another.  On Earth, we see the effects of this spaghettification in the form of tides.

1.  What causes spaghettification?

2.  How much gravitational force do the Sun and Moon each exert on 1,000,000 pounds of water?

3.  Even if there were no water on Earth, there would still be tides, just as there are tides on the Moon.  Describe these tides.

4.  Why do we always see the same side of the moon?

5.  Is the Earth's 24 hour rotational period speeding up or slowing down over time? Answer

Today: 

• Check/review homework

  • #14 and 15 from  Notes:  Circles, Gravity, Kepler   Solutions

  • MC from Practice -- Mr. Pennington's 2015 test.  Solutions

• T

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework: 

• Complete the problems from Practice -- Mr. Pennington's 2015 test.  Solutions (although #5 and #7 is in radians).  Video tips on solving the problems, including 5 and 7 in linear terms.

• Little test/big quiz next Wednesday.  The test will cover circular motion, gravitation, and Kepler's Laws.

Class 33

Warm Up: 

1.  At what approximate date is the Earth orbiting with the fastest speed?  When is it orbiting the slowest?

2.  Rank our seasons in order of length. Answer

3.  How are our solstice and equinox dates determined?

Today: 

• Check/review homework -- Elliptical Orbits Activity 

• Finish Notes -- Kepler's 1st and 3rd Laws --  Notes:  Circles, Gravity, Kepler   Solutions solution to #10 with 3rpm

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework: 

•  #14 and 15 from  Notes:  Circles, Gravity, Kepler   Solutions

• Complete  the multiple choice section of Practice -- Mr. Pennington's 2015 test.  Solutions (although #5 and #7 is in radians).  Video tips on solving the problems, including 5 and 7 in linear terms.

Class 32.5

Warm Up: 

Are astronauts weightless when they are in the international space station?  Is this candle weightless? 

Today: 

• Check/review homework.  Notes:  Circles, Gravity, Kepler   Solutions solution to #10 with 3rpm

• Kepler's Laws

• Elliptical Orbits Activity 

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework:  Finish the elliptical orbits activity. Elliptical Orbits Activity 

Class 32

Warm Up:  Hank is carrying a very wide tray of sand that won't fit through a doorway.  How can Hank get the tray through the doorway without spilling the sand?

Today: 

• Do you have a zero for your home run problem or your rocket analysis?

• Check homework.  Notes:  Circles, Gravity, Kepler   Solutions solution to #10 with 3rpm

• Newton's law of Gravitation

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework:  The following can be found in Notes:  Circles, Gravity, Kepler   Solutions solution to #10 with 3rpm

• Complete whatever remains of "circular motion example problems 1-2" or "circular motion practice problems 1-3" 

• Complete "various practice problems" 11-13.

Class 31.5

Warm Up:  

Consider an object tied to a string that is being swung in horizontal circles.  What forces are acting on the object?  What forces are acting on the string?

Today: 

• Return things

• Chapter 6 (Circular Motion and Gravitation)

  • Brief look in online textbook -- Chapter 6.2 -- Centripetal Acceleration

  •  Notes:  Circles, Gravity, Kepler  Solutions solution to #10 with 3rpm

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework: 

• Problem #10 of "various problems" in Notes:  Circles, Gravity, Kepler   Solutions solution to #10 with 3rpm

Class 31

Warm Up:  

 If you made a hole straight through the Earth, where would the hole come out on the other side?

(antipodes map)

Today: 

• Quiz

• Test corrections due today

• Chapter 6 (Circular Motion and Gravitation)

  • Brief look in online textbook -- Chapter 6.2 -- Centripetal Acceleration

  •  Notes:  Circles, Gravity, Kepler  Solutions solution to #10 with 3rpm

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework: 

• none

Class 30.5

Warm Up:  

According to physics lore, if you made a hole through the center of the Earth, and jumped in, you would readch the other side in approximately 42 minutes (assuming no friction). 

1. How could this be calculated using Newton's Law of Gravitation?

2. It turns out that the trip would not actually take 42 minutes.  Why?  Would the trip actually be longer or shorter?

3.  What if there were air resistance?

4. Where would you come out? 

(antipodes map)

Excel spreadsheet -- falling through the earth

Today: 

• Please change your spreadsheet share settings to "anyone at ewsd with a link"

• Review homework -- Another practice quiz -- from two years ago.  Video showing solutions

• Begin Chapter 6 (Circular Motion and Gravitation)

  • Brief look in online textbook -- Chapter 6.2 -- Centripetal Acceleration

  •  Notes:  Circles, Gravity, Kepler  Solutions solution to #10 with 3rpm

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework: 

• Corrections for Test 3 (Newton's Laws in 1-D) due tomorrow

• Quiz tomorrow over Newton's Laws in 2-D. 

Class 30

Warm Up:  

A Google search result says the acceleration of gravity on Earth is 9.807m/s².  For multiple reasons,that is almost always not the precise acceleration of a falling object. 

1. What are those reasons?

2. When would this be the exact acceleration of a falling object?

Today: 

• Check/review homework -- Practice Quiz over Newton's Laws in 2-D.  Spreadsheet solutions to practice quiz

• Return papers -- there's a video on my youtube channel that will help you with the rocket analysis number 11

• Another practice quiz -- from two years ago.  Video showing solutions

Online Textbook (OpenStax) Reading: 

• Chapter 6.2 -- Centripetal Acceleration
• Chapter 6.3 -- Centripetal Force

Homework: 

• Due on Friday, 11/30:  Corrections for Test 3 (Newton's Laws in 1-D)

• Optional -- Another practice quiz -- from two years ago.  Video showing solutions

• Quiz on Friday over Newton's Laws in 2-D.

Class 29.5

Warm Up:  

A waiter is carrying a chunk of bone, basted with synovial fluid, on a flat, bone tray.  The tray is angled at 45º, as shown.  Why doesn't the bone chunk slip off of the tray?  What would the waiter need to do in order to stop and turn around, without touching the bone, and without cau

Today: 

• Distribute Donuts

• Check/review homework -- Masses Hanging and Dragged at Angles Solutions to #1 and #2  solutions to #3 and #4

• Return baseball home run problem -- discuss grading

• Get Practice Quiz over Newton's Laws in 2-D. 

Online Textbook (OpenStax) Reading: 

• 4.5 Normal, Tension, and Other Examples of Forces

• 4.6 Problem-Solving Strategies 

• 4.7 Further Applications of Newton’s Laws of Motion

Homework: 

• Due on Friday, 11/30:  Corrections for Test 3 (Newton's Laws in 1-D)

• Practice Quiz over Newton's Laws in 2-D.  Spreadsheet solutions to practice quiz  Due tomorrow.

• Quiz on Friday over Newton's Laws in 2-D.

Class 29

Warm Up:  

A 1kg mass is suspended by a string from the ceiling of a train car.  The front and rear of the car are open, so the mass is exposed to the oncoming wind.  The velocity of the train and the angle in the diagram both remain constant. [Air density = 1.2kg/m³.  C_{d sphere} = 0.45.  A_sphere = 0.05m²]

1.  How would we draw the forces acting on the sphere?

2.  Given g = 10m/s², what is the tension in the string?

3.  What is the velocity of the train?

Today: 

• Check/review homework Bodies on Inclines (abbreviated)  Answers (and some solutions ) to Bodies on Inclines 

• Donuts tomorrow

• Turn in the rest of your assignments:

  • Water rocket analysis (one per group) -- put it in the wire basket

  • Your projectile with drag spreadsheet.  Submit a link using this form.

  • Most efficient home run.  Put your sheet in the wire basket. 

• Masses Hanging and Dragged at Angles Solutions to #1 and #2  solutions to #3 and #4

Online Textbook (OpenStax) Reading: 

• 4.5 Normal, Tension, and Other Examples of Forces

• 4.6 Problem-Solving Strategies 

• 4.7 Further Applications of Newton’s Laws of Motion

Homework: 

• Complete the rest of Masses Hanging and Dragged at Angles Solutions to #1 and #2  solutions to #3 and #4

• Due on Friday, 11/30:  Corrections for Test 3 (Newton's Laws in 1-D)

Class 28

Warm Up:  

The picture on the right shows how a chain can be used to pull a stuck car out of the mud.  All that is required is a small sideways force applied to the center of the chain.  Why does this work?

Today: 

• Intro to Bodies on Inclines (abbreviated)  Answers (and some solutions ) to Bodies on Inclines  Low resolution video from 2 years ago (first page of handout)

• Enter your rocket flight times into the form (Rocket contest results)

• Work time.

 Assignment Due Dates: 

• Due tomorrow (11/16) -- Water Rocket Analysis (with your partner)

• Due tomorrow (11/16) --  As a group, finish and debug your own spreadsheet and submit it using this form.

• Due tomorrow (11/16) -- Complete individually. Most efficient home run.Video help, part 1 Video help, part 2 (the graph)

• Due on Monday after break (11/26) -- Ordinary homework -- Bodies on Inclines (abbreviated)  Answers (and some solutions ) to Bodies on Inclines

• Due on Friday, 11/30:  Corrections for Test 3 (Newton's Laws in 1-D)

Warm Up:  

1. How does Clifford Heath's water rocket simulator work?  What can we learn from it?

2. How could you modify your spreadsheet to calculate:  1) "crashdown speed?" 2) Δx?

Today: 

• Work on the Water Rocket Analysis (with your partner) -- Due tomorrow..

  • Here's a link to your rocket pre-launch data that you submitted before we launched.a

  • Link to Clifford Heath's  Water rocket simulator

• Get the home run problem (due on Friday)

 Assignment Due Dates:  These assignments are not optional.  If you do not complete them, they will count as zeroes.

• Due on Thursday (11/15) --  As a group, finish and debug your own spreadsheet and submit it using this form.

• Due on Thursday (11/15) -- Water Rocket Analysis (with your partner)

• Due on Friday (11/16) -- Complete individually. Most efficient home run.

Class 27

Warm Up:  Two boxes are initially at rest, relative to a the elevator in which they sit. When a person exerts a 200N rightward force over a time interval of 1 second, the 20kg box moves a distance of 1.38m rightward.   What is the 10kg block's x displacement during that same time interval?

Today: 

• Bonus problem solutions should be turned in.

• Work on the Water Rocket Analysis (with your partner) -- Due on Wednesday.

  • Here's a link to your rocket pre-launch data that you submitted before we launched.

 Assignment Due Dates:  These assignments are not optional.  If you do not complete them, they will count as zeroes.

• Due on Thursday (11/15) --  As a group, finish and debug your own spreadsheet and submit it using this form.

• Due on Thursday (11/15) -- Water Rocket Analysis (with your partner)

• Due on Friday (11/16) -- Complete individually. Most efficient home run.

Class 26.5

Warm Up:  

Suppose someone straps a stuffed koala to a rocket and then launches the koala and rocket directly upward.  The rocket thrust lasts for 1 second and provides a constant force of 1,000N.  During thrust, the average mass of the koala + engine + fuel + harness = 10kg.

Ignoring air resistance, calculate the maximum height reached by the koala?  For ease, you can assume that g=10m/s².

Today: 

• 7/8 --

  • Turn in and review previous homework (I forgot about it on Friday)

  • Column Q and the orange cells

    • Time aloft formula -- undo the fix that I mentioned in last class.  Talk about why.

• Work on the Water Rocket Analysis (with your partner) -- Due on Wednesday.

  • Here's a link to your rocket pre-launch data that you submitted before we launched.

Tomorrow:  Work time to finish whatever you need to finish.

 Assignment Due Dates:  These assignments are not optional.  If you do not complete them, they will count as zeroes.

• Due on Thursday (11/15) --  As a group, finish and debug your own spreadsheet and submit it using this form.

• Due on Thursday (11/15) -- Water Rocket Analysis (with your partner)

• Due on Friday (11/16) -- Complete individually. More applications of the projectile with drag spreadsheet

  1. Most efficient home run:  Video help, part 1 Video help, part 2 (the graph)

     1. What is the minimum speed at which a baseball must leave a bat in order to reach the fence (in the air) 340 feet away?  What is the angle for this hit?  Assume that the density of the air is 1.22kg/m³, the mass of the baseball is 0.145kg, the circumference of the ball is 0.23m, and the ball's drag coefficient is 0.45.

     2. Create a graph of Y position vs X position to show this baseball's flight path.  Adjust the X and Y axes so that the scales are approximately equal and, therefore, the shape of the flight path is undistorted.

Class 26

Warm Up:  

1.  What purpose does the formula in column Q serve?

2.  Why don't the first several rows in column Q have formulas?

Today: 

• Overall test distribution

• Check homework

• Important notes for finishing your own spreadsheet (due Tuesday)

  • Column Q and the orange cells

    • Time aloft formula -- undo the fix that I mentioned in last class.  Talk about why.

  • Modifying the Xdrag formula to improve spreadsheet versatility.

• Collect data for the Water Rocket Analysis (with your partner)

• MSTWDS

 Homework: 

Class 25.5

Warm Up:  

A 1kg mass is suspended by a string from the ceiling of a train car.  The angle shown remains constant.

1. Describe the motions of the mass and the train car in qualitative terms.

2.  How can we find the tension in the string?

3.  How can we describe the motions of the mass and the train car in quantitative terms.

Today: 

• Look at tests.  Until everyone has taken the test (?), come to flex to work on corrections.

• The mysterious column Q, and the orange cells -- fix for time aloft.

• If you have a partner, share your spreadsheet, and make your own personal copy.

• Finish the spreadsheet to analyze a projectile (e.g. a coasting rocket) that is experiencing drag.

  • Spreadsheet Template:  Projectile with drag   Directions Video showing how to create the spreadsheet

  • Correct calculations

• MSTWDS

 Homework: 

• Due Tomorrow:  Find a Rocket's Drag Coefficient (and more) using your spreadsheet.

Class 24.5

Warm Up:  

Find the acceleration of each block and the tensions in the two strings.  To make your work easier, use g=10m/s²

Assume that the pulleys and strings are massless and frictionless.

Today: 

• Student led test review -- until it there are no more questions

•  A5/6 -- one Gucci/Supreme rocket to disassemble

• The mysterious column Q, and the orange cells.

• Finish the spreadsheet to analyze a projectile (e.g. a coasting rocket) that is experiencing drag.

  • Spreadsheet Template:  Projectile with drag   Directions Video showing how to create the spreadsheet

  • Correct calculations

• MSTWDS

 Homework: 

• Test on Wednesday. 

  • What's on the test

  • Options:  1) note card of your making  2) provided formulas    3)  Neither note card nor formulas, plus approximately 3% extra credit -- you must commit to this before the test.

  • Begin making a "note card" if you want one.  Requirements/limitations:  no more than 80in² of surface area; original handwritten copy, created by you.

Class 24

Warm Up:  

1. How does NASA simulate weightlessness?

2. You are trying to transfer some drippy sauce across a dinner table using only a drippy spoon.  The sauce needs to go from the pot to your plate without dripping.  Touching only the spoon, how can you make this happen?

3.  What would happen if you were standing on a bathroom scale in an elevator, and the elevator suddenly began to accelerate downward at 1g?

4.  What is the source of the "butterflies in the stomach" when we fall?

Today: 

• A7/8 -- two more rockets to disassemble.

   

• Create a spreadsheet to analyze a projectile (e.g. a coasting rocket) that is experiencing drag.

  • Spreadsheet Template:  Projectile with drag   Directions Video showing how to create the spreadsheet

  • Correct calculations

• MSTWDS

 Homework: 

• Test on Wednesday. 

  • What's on the test

  • Options:  1) note card of your making  2) provided formulas    3)  Neither note card nor formulas, plus approximately 3% extra credit -- you must commit to this before the test.

  • Begin making a "note card" if you want one.  Requirements/limitations:  no more than 80in² of surface area; original handwritten copy, created by you.

Class 23.5

Warm Up:   The figure on the right shows Atwood's Machine.  Write an equation for the acceleration of the masses in terms of m₁, m₂, and g.  You may assume that the rope is massless and that there is no friction.

Today: 

• Check/review homework:  Some more practice questions/ problems.  Solutions

• Test review. 

  • What to study

  • Some more practice questions/ problems.

• A7/8 -- two more rockets to disassemble.

   

• Create a spreadsheet to analyze a projectile (e.g. a coasting rocket) that is experiencing drag.

  • Spreadsheet Template:  Projectile with drag

  • Correct calculations

 Homework: 

• Test on Wednesday. 

  • Options:  1) note card of your making  2) provided formulas    3)  Neither note card nor formulas, plus approximately 3% extra credit -- you must commit to this before the test.

  • Begin making a "note card" if you want one.  Requirements/limitations:  no more than 80in² of surface area; original handwritten copy, created by you.