Class

Warm Up:  

1. What's the point of this GIF?

2.  What is modulation?

3.  What is pulse-width modulation?

Class

Warm Up:  

1.  What do polarized glasses do?  How are they useful?  How do they work?

2.  How does the "Amazing Secret Monitor" work?

Class

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?  How does this relate to seals?

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?

Class

Warm Up:  

1.  How can you find the North Star?

2.  Why won't this work in 3,000 years?

3.  How does this relate to Frisbees' embarrassing habit of twisting in the air, falling, and then rolling in a circle on the ground?

Class

Warm Up:  Get a lens. 

1. Find the lens' focal length.

2. Hold the lens so that you can see focused real image.

3.  Hold the lens so that you can see a focused virtual image.

Warm Up:  None

Class

Warm Up:  

Class

Warm Up:  

1.  How does depth perception work?  How, for example, when we see something that is near and small, how do we know it's not far and large?

2.  Sometimes small children look out of windows of moving cars and think the moon is following them.  Have you ever had this experience?

3.  How can we use parallax to determine the distance to a star?

Class

Warm Up:  

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

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

Warm Up:  Contemplate this -- the speed of light in a vacuum is always constant, relative to any observer. [Interesting web page explaining all of this]

Warm Up:   Refraction is the "bending" of waves as they pass from one medium to another.  Rainbows are the result of reflection and refraction.

Warm Up:   None

Warm Up:  

Warm Up:  

Warm Up:   None

Class

Warm Up:   In today's lab, you're going to submerge an open pvc pipe in water.  Then, pulling the pipe vertically out of the water, you will search for positions at which the pipe resonates with a 512Hz tuning fork (plus another one).

1.  Explain what is going on when the pipe resonates.

2.  Draw the standing waves for the the shortest pipe length that will cause resonance.

3.  Draw the standing waves for the next shortest pipe length.

4.  What is the ratio of this short pipe length to the long pipe length?

5.  Which pipe length is producing its fundamental harmonic?

6.  How does this situation contradict what I have told you about harmonics?

Class

Warm Up:  

Class

Warm Up:   What do you think this simulation is supposed to demonstrate?  How does it relate to riding in a car with one window open?

Class

Warm Up:   How does a speaker work?

Class

Warm Up:   What would we hear if we listened to these two sounds, simultaneously?

Class

Warm Up:  

1. How does a bow cause a string to vibrate at its resonant frequency?

2.  In light of this, how do you increase volume on a bowed instrument?  Why does this work?

Warm Up:   How can you find out whether a song is in a major key or a minor key?

Warm Up:   Can you break glass with your voice?

Class

Warm Up:  

Class

Warm Up:   This video shows standing waves.  They're like the string waves you saw in here, but they're on a planar sheet of metal, rather than a linear string.  Does the white substance (salt? powder?) settle at nodes or at antinodes? 

Class

Warm Up:   What's happening in the "Amazing Water and Sound Experiment?"

1. Return magnetism project grading sheets.  You can make corrections by explaining whatever you lost points for, on paper.

2. Electric Guitar Project:

Homework:  None

Class

Warm Up:  

1.  What's the best way to remove wire (or thread, fishing line, etc) from a spool, quickly?  Does this method have any drawbacks?

2.  Do you know how soldering works?

Class

Warm Up:   Why does this string look like this?

Class

Warm Up:  

1.  What can we do with these generators?

2.  What do you think is inside them?

Short Video:  Motor vs Generator

Class

Warm Up:   What is this thing?  How does it work?

Class 6

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?

Class 6

Warm Up:   We have three identical corded drills and one driver bit.  With no additional materials, and without disassembling a drill, how can we provide electrical power to two of the drills by plugging just one of them into the wall?

Class 6

Warm Up:  

 1.  How does an induction stove work?  What happens if you put a big (1kg) aluminum plate on top  of a powerful induction stove?  Why? 

2. Why don't people use aluminum pots on induction stoves? 

3. What is levitation melting?

Class 6

Warm Up:  

The "Ring Launcher" launches conducting rings.  It also lights lightbulbs without contact.  How does it work?

Homework:  

• #11-12 on page 4 of the packet. 

Warm Up:  

Guess what happens if I drop a strong magnet into a vertical copper pipe?

Warm Up:  

Nonw

Class 6

Warm Up:  

1.  Will the top of the motor coil rotate toward us or away from us?

 2.  When I make a motor like this, I sand both ends of the coil wire, but I only sand half of each end (as shown in the close-up).  Why do I do this? 

Class 6

Warm Up:  

This is one way to build a buzzer.  Can you explain how it works?

Homework:   Complete #1-14 on pages 5  of the packet   Solutions  Video explanations

Class 6

Warm Up:  

1.  What's wrong with this diagram?

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

Homework:  Complete 1-5 on packet p. 3.  Video help  Answers: 1. CCW through coil    2. Force is attractive    3.  Rightward    4. Top of coil is pushed away from us (into the paper)   5.  Positive terminal is on the left

Class 6

Warm Up:   A digital multimeter, like the one on the right, can be used to measure voltage (voltmeter mode) and current (ammeter mode).  In this class, we only use the voltage measuring function, because measuring current can be tricky and troublesome. 

When we use a multimeter, we "insert" it into the circuit, so that charge flows through the multimeter.

1a.  To measure voltage (potential drop) across a resistor, should we "insert" the multimeter in parallel or in series with the resistor?

1b.  In voltmeter mode, is it best for the multimeter itself to have a high resistance or a low resistance?  Why?

2a.  To measure the current flowing through a resistor, should we insert the multimeter in parallel or in series with the resistor?

2b.  In ammeter mode, is it best for the multimeter to have a high resistance or a low resistance?  Why?

3.  In this class, we don't measure current with our multimeters because it results in a lot of blown fuses. Can you guess how this happens?

4.  What is the purpose of a fuse?

Homework:  Here's what's on the test.  Take a look.  If you have questions about anything, ask them tomorrow or on Friday.  The test will be on Monday.  There is no other homework.

Class 6

Warm Up:  Can you anticipate what comes next in Mr. Chase's energy distribution analogy for circuits?

Homework:  No homework

Class 6

Warm Up:  Mr. Chase collected data for the graph on the right using a light bulb like the ones you will be using in class.

1.  What does the slope of the graph represent?

2.  What does this graph tell you about light bulbs in circuits?

3.  How many "unique currents" are there in the circuit shown in yesterday's warm-up?

Homework:   Two number twos...

• Complete #2 (the bottom one) from p.19 of the packet.  Solutions 
• Complete #2 from this link... More Kirchoff's Laws Practice (#2)   Solutions   Video Solutions

Class 6

Warm Up:  In a circuit, a "junction" is a point at which three or more conducting paths coincide. A "loop" is a conducting path that departs from some starting point and returns to that starting point without traversing any other point twice. Video of this in PhET DC Circuit Lab

1.  How many junctions are in the circuit?

2.  How many unique loops are there in the circuit on the right?

3.  True or false:  The amount of current flowing into any junction must always equal the amount of current flowing out of the junction.

4.  True or false:  If a charged particle takes one full trip around any loop, the overall voltage experienced (change in potential) will always be exactly zero.

Warm Up:  None

Class 6

Warm Up:   Watts is the unit for power.  This includes electrical power.

1.  Here's an analogy... Dachsund : Dog :: Maine Coon : Cat.   Complete this string of analogies...

Newton : kgm/s² :: Volt : _____ :: Ampere : ______ ::Watt : ________

2.  Using dimensional analysis, can you suggest a formula for electrical power?

3.  How does an incandescent bulb work?  How can a bulb's brightness be increased or decreased?

Homework:    Due on Thursday -- If you're not retaking the Electrostatics Test, you can work on this in class tomorrow.

• Resistivity and Power (p. 9-10). One resistivity problem.  Here's the problem.  Here's the solution.
• Mr. Pennington's Test -- Packet p. 20-24  Solutions  Multiple Choice Video   Problems Video
• Not important (optional) -- finish the parts of the equivalent resistance challenge (p.15,16) that we skipped.  This involves merely calculating power in a few instances.

Class 6

Warm Up:   The figure on the right clarifies a formula that can be used for calculating the resistance (R) of a wire.  Can you figure out what it means and how it makes sense?

table of resistivities

Class 61.5

Warm Up:  

1.  According to the labeling, how many joules of energy are stored in this battery when it is fully charged?

2. If a fully charged battery like this one were powering a 100% efficient lifting device, how much mass could it lift a distance of 1 meter?

Class 61

Warm Up:  

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

1.  Voltage is like _____

2.  Current is like _____

3.  Resistance is like _____

Class 60.5

Warm Up:   In this D.C. Circuit PhET simulation, we can use a virtual device to measure voltage.  The circuit is powered by a 9V battery.

1.  What does D.C. mean, in this context?

2.  What is voltage?

3.  Why do we get different voltage measurements if we put the two probes in different locations within the circuit?

Warm Up:   None

, 3/17/22

Warm Up:   The diagram on the right comes from the online textbook. 

1. What do you think is the point of the diagram?
2. How are "force" and "pressure" different?
3. How do these questions relate to current, circuits, and the water analogy for circuits?

Class 59

Warm Up:  

1.  Do birds get shocked when they land on power lines?  Why or why not?

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?

Class 58.5

Warm Up:   In the tesla coil video on the right...

1.  What is creating the music?

2.  Why is the guy wearing a metal suit?

3.  Why are the sparks jagged? (PhET)

4.  What else do you notice the sparks doing?

Homework:  18.5 Practice -- except for number 2! (packet pages 13-14):  18.5 Practice Solutions Pennington 18.5 Practice Solutions 

Class 58

Warm Up:  

Which of the following should be stated with the greatest certainty? Why?

A)  The balloons have the same net charge

B)  The cat and the foam "peanuts" have opposite net charges.

C)  Both A and B are correct.

D)  None of these answers is (are) correct.

Class 57.5

Warm Up:  

1. What is a spark? Breakdown voltages,

2.  What is a Jacob's Ladder?  What is its purpose?

spark gap

Class 57

Warm Up:  

1.  Diagram C shows two conductors with excess positive charges.  Why do the excess charges reside on the conductors' surfaces? 

2.  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?

Class 56.5

Warm Up:  

The deceptively complicated case of the electrified pickle...

Warm Up:   None

Class 55.5

Warm Up:   What's going to happen at the moment that this Van de Graaff Generator is turned on?  Why? 

Class 55

Warm Up:  

1. How does a Van de Graaff Generator Work?

2. What light does the VDG shed on John Travoltage?

Links:

• MIT video --  VDG demo

• Good, detailed explanation of Van de Graaff

• More about how a VDG works

Things to try:

• Hair-raising
• Pith ball
• "Hero Engine"
• Putting out fire

Class 54.5

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 positive 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:  

Class 54

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? Triboelectric Series

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

3.  What events contributed to this gas station fire?

Today: 

• Return tests.  The test retake (circular motion and gravity) will be offered next Tuesday.
• Get Unit 8 Packet  PDF Version
• Preview of things to come:  Electrostatics, Electric Current/Circuits, Electricity and Magnetism, Waves/Sound, Optics

• Notes (packet p. 1-3): 18.1 and 18.2 (Static Electricity & Charge, Conductors and Insulators)

  •  Filled-in Notes

  • Video from 2018-19 class -- Sorry for the "terrifying beeping."

• Vsauce Video: We can't really touch anything

Warm Up: 

None

Today: 

• Test

Homework: 

• None

Class 52.5

Warm Up:  What's the point of making an apparatus such as the one on the right?

Today: 

• Check/review homework
• What formulas will be given/not given?
• One more time through the test...

Homework: 

• Test tomorrow

Class 52

Warm Up: 

Today: 

• Check/review homework
• 7/8 -- finish going over the homework that was due yesterday
• 7/8 -- Mr. Pennington's 4 minute drill -- with an extra minute or two thrown in
• Take a look at #8 on page 18, and discuss how it contains Kepler's 3rd Law -- and then some.
• Hard and bouncy spheres -- Marble dropped on an anvil;  Steel Ball dropped on an anvil

Homework: 

• Practice test #2 Problems (packet p. 15-16) Answers/Solutions
• Complete # 7 and #8 on p. 17 and 18
• Optional Bonus -- see yesterday's homework (due on Thursday, by the end of class)

Class 51.5

Warm Up: 

Today: 

• Check/review homework
• 7/8 -- discuss leaving early and masks
• Mr. Pennington's 4 minute drill -- with an extra minute or two thrown in
• Take a look at #18 on page 8, and discuss how it is Kepler's 3rd Law -- and more.

Homework: 

• Practice test #2 Multiple choice only (packet p. 13-14) Answers/Solutions
• Optional Bonus, due on Thursday -- for an extra 1 percent on the test, calculate the minimum number of gs a driver would need to tolerate in order for their car to maintain constant contact with a 10m radius loop the loop (and show your work!) -- assuming that the driver does not use the accelerator or the brakes once they enter the loop, and that no energy is lost (to friction,etc.) during the loop traverse.  To simplify matters, further assume that the centers of mass of the driver and the car are traveling in a 10m radius loop.

Class 51

Warm Up: 

Today: 

• Test retake
• Work time (see homework, below)

Homework:  All of this is due on Monday.  Tomorrow is the retake day and work time during class.

•  #14 & 15 on packet p.6 --  Solutions  
• Practice test #1 (packet p. 9-12) Answers/Solutions Video Explanations

Class 50.5

Warm Up: 

Class 50

Warm Up:   

Today: 

• Kepler's 1st 2 Laws -- Orbits Activity (Instructional Video from Last Year)
• Unit 7 Packet (pdf version of unit 7 packet)

Homework: 

• Finish the orbits activity (pages 7-8)
  • Directions -- Video from Last Year)
  • Discussion -- Video from last year.   I discussed the answers near the beginning of this video.

Class 49.5

Warm Up:   How does this yo-yo work? What do the springs and steel balls do?

Today: 

• Check/review homework
• No new notes -- Kepler's Laws tomorrow

Homework: 

• #10 & 11 on p. 5  Solutions (including p. 5)    Video Solutions to 4, 8, 10, 12, 13.
• #1-5 on p. 17 Answers/Solutions
• Test retake on Friday

Class 49

Warm Up: 

Today: 

• Return tests
• Notes: Circular motion and Gravity -- p.1 & 3 of packet  Unit 7 Packet (pdf version of unit 7 packet)
  • Filled-in notes
  • Video from last year's class

Homework:  Solutions    Video Solutions to 4, 8, 10, 12, 13.

• #1-3 on p.2
• # 8 on p.3
• #12-13 on p.5-6

Warm Up:  None

Today: 

• Test

Homework: 

• None

Class 47.5

Warm Up:  How do you remove the coin from the YOT?

Today: 

• Check/review homework
• Questions about the test?
• If you want more practice, here's one of Mr. Pennington's old tests... Mr. Pennington's Old Momentum Test.  Answers/Solutions.  I can print one if you want.

Homework: 

• Study for tomorrow's test.

Class 47

Warm Up:  This Top Gear episode features a Renault Modus (compact car) vs. Volvo wagon in a head-on crash. 

1.  What will happen?

2.  Which is safer, a car that crumples in a crash or a car that is more rigid?

Today: 

• Check/review homework
• If you want more practice, here's one of Mr. Pennington's old tests... Mr. Pennington's Old Momentum Test.  Answers/Solutions.
• New unit -- circles and gravitation
• Unit 7 Packet (pdf version of unit 7 packet)
• Introduce topic and solve "example problems" on packet page 1.   Solutions  Video of class from last year -- pretty good, I think
• Brief look at centripetal acceleration derivation in online textbook.
  • Chapter 6.2 -- Centripetal Acceleration
  • Chapter 6.3 -- Centripetal Force

Homework: 

• Circular motion problems 1-3 on page 2 of the Unit 7 packet  Solutions
• Test on Thursday -- be ready.

Class 46.5

Warm Up:  Suppose I place some foam on my table top, and then I shoot it with the two darts in the picture, using the same Nerf ^® gun.  Compare the effects of the two darts impact on the motion of the foam.

Today: 

• Check/review homework
• Finish page 5 of the notes

Homework: 

• Complete the short answer section of the practice test, (#1-3 on pages 14 and 15) Some answers
• Test on Thursday

Class 46

Warm Up:  The photograph on the right shows a homemade "Gauss Gun."  In the picture there are 9 steel spheres and 4 cube-shaped magnets.  The operator is preparing to roll one sphere toward a magnet.  What will happen, and how will it work?

Today: 

• Check/review collisions lab and questions (p.11-12) p. 12 answers
• 10 minutes to wrap-up and submit the ballistic pendulum "lab reports."  Share your results.
  • Use my ballistic pendulum initial velocity calculator to check your velocity calculation(s)
• Work time -- start on the homework

Homework: 

• Two things... 1) multiple choice questions on page 13 of the packet. Answers --   2) problems on pages 15 and 16 of the packet Solutions
• Test next Thursday

Class 45.5

Warm Up: 

1) How can we find the coefficient of restitution of this racquetball?

2) What's wrong with question number 1?

Today: 

• Finish ballistic pendulum data collection. 
• Make sure that you have all of the data for the collisions lab.
• If you have time, begin working on the collisions lab calculations and questions and/or calculate your ballistic pendulum velocities.

Homework: 

• Complete the collisions lab calculations and questions (p.11-12)  Use this formula to calculate restitution --
• Ballistic pendulum labs are due tomorrow -- you can have a few minutes (up to 10 minutes) in class to finalize them and turn them in.

Class 45

Warm Up: 

Today: 

• Check/review homework
• Ballistic Pendulum Activity: 
  • Design and conduct an experiment to answer one of these questions.  Fill out the lab sheet as you go. Time is short, so keep it simple.  You may just have time for one trial.
    • How does projectile mass projectile affect the impulse of the launch?
    • How does barrel length affect projectile velocity?
    • Other -- make up your own interesting and testable question.
  • Make a cylindrical projectile (or projectiles) with a diameter no greater than 1.5cm and a length no greater than 1.5cm.
• Unit 6 Packet (Unit 6 Packet -- PDF Version)

Homework: 

• Change of plans -- this is not due tomorrow.  But work on it if you want --  collisions lab questions.   Use this formula to calculate restitution --

• Ballistic pendulum labs are due on Friday.

Class 44.5

Warm Up:  A cart is released from the top of a ramp.  The cart rolls a distance d_c to the bottom of the ramp, hits a force sensor, and rebounds up the ramp a distance of d_s.

1.  "If we apply this kinematics formula (see diagram) to both the cart's descent and ascent, we can assume that the acceleration is the same in both cases."  Is the previous statment true?  Explain.

2.  Write a formula for coefficient of restitution, given a cart's closing distance (d_c) and separation distance (d_s) in this scenario.

Today: 

• Check/review homework
• Notes:  Ballistic pendulums, pages 5 and 6.Video from last year's class
  • Notes key
• On yesterday's lab sheet, use your average closing distance and separation distance data to calculate your cart's coefficients of restitution.
• Unit 6 Packet (Unit 6 Packet -- PDF Version)

Homework: 

• Complete #16-18 on page 10 of the packet.  The answer to number 18 is at the bottom.  Answers to 16 and 17 are provided with the solutions. 

  • Problem Solutions

• Work on Collisions Lab questions?  They are due on Thursday

Class 44

Warm Up: 

Today: 

• Does anyone want me to add a science course recommendation? (even if another teacher has already entered recommendations)
• Check/review homework
• Collisions Lab (packet pages 11-12)
• Unit 6 Packet (Unit 6 Packet -- PDF Version)

Homework: 

• Finish Lab questions -- Due on Thursday
• Problems 11-13 on packet p. 8-9.  Answers are at the bottom of page 10.

  • Problem Solutions

Class 43.5

Warm Up: 

Today: 

• Check/review homework
• Notes:  Elastic/Inelastic Collisions and Coefficient of Restitution (p.3-4 of the packet)
  • Notes key  (In the notes key, I made some mistakes on #22 -- coefficient of restitution example -- I believe the answer is correct, but the variables are mislabeled confusingly.)
  • Video of notes from last year

Homework: 

• Problems 14 & 15 on packet p. 9-10.  Answers are at the bottom of page 10.

  • Problem Solutions

Class 43

Warm Up:  Let's actually solve the warm-up problem from yesterday.

Today: 

• Unit 6 Packet (Unit 6 Packet -- PDF Version)
• Notes:  Momentum, Impulse, and Conservation of Momentum (p.1-3 of the packet)
  • Notes key
  • Videos from last year:
    • Momentum and Impulse Notes Video -- pages 1-2
    • Conservation of momentum notes video -- page 3

Homework: 

• Problems 1-10 on packet p. 7-8.  Answers are at the bottom of page 10.

  • Problem Solutions

  • Video explaining problems 1-6

  • Homework help video for problems 7-10

Class 42.5

Warm Up:  When the two blocks collide, they stick together.  What is the shared velocity of the two blocks after the collision?

Today: 

• Donuts
• Exams
  • Take a look -- don't forget to return
  • Score distribution before adding 3.5 points

• Course Recommendations for Juniors -- promotional materials...
  • APES
  • Designing Solutions to Global Problems

Homework: 

• None

Class 41.5

Warm Up:  A student wants to launch a pencil as far as possible using energy stored in exactly two rubber bands.  The sharpened pencil has fins on its eraser end and a protruding paper clip attached near the nose.  The pencil is to be launched by a looped string that connects to the paper clip on one end and the rubber bands on the other.  If the teacher has placed a limit on the total amount of force that can be used in launching process, would any one of these configurations be better than the others?  Explain.

Today: 

• Last minute exam questions?
• Disassemble trebuchets.  If you really and truly want to keep yours, you can keep it.
• Trebuchet slides are due at midnight -- for contest purposes.  You can turn it in later, but that may be too late for the contest.

Homework: 

• Exam review

Warm Up:  None

Today: 

• Midterm review --
  • **The formula list in Google Classroom has been updated**
  • Updated Google Doc with notes from this week's classes -- In-Class Midterm Review
  • Back to Kinematics in 2-D -- Range Formula
  • Finish forces
    • Problems with Forces and kinematics
    • Specific Tools needed to solve force problems
      • Weight
      • Tension/Normal Force/Contact Force
      • Friction
    • 2-D force problems
      • Static problems
      • Blocks, pulleys, and ramps
  • Energy -- take a look at the formulas on the formula sheet
• Project work time

Homework: 

• Exam prep

Warm Up:  What is an algorithm?

Today: 

• Link to notes from last class
• Midterm review -- Newton's Laws (Forces)

Homework: 

• Exam prep

Warm Up: 

1.  List all of the variables that show up in kinematics problems. 

2.  List all of the kinematics formulas. 

3.  In projectile motion problems, which

Today: 

• "Notes sheet" options. 
  • Option 1: You can hand-write (or draw) anything you want on both sides of an 8.5"x11" sheet of paper, and use that paper on the exam.  You, personally, must make your own notes sheet.  You must turn in your notes sheet with your exam.
  • Option 2:  You can opt out of the notes sheet and recieve an extra 2% on your exam grade.
  • Not an option: using a formula sheet that I provide.  If you want the formulas, put them on your notes sheet.
• Midterm review -- Kinematics (1D and 2D)?
  • Questions about the multiple choice review material?
  • Problem Solving (work through example problems) -- Necessary information and algorithm
    • Givens -- stated and implied
    • Trig functions and inverse functions, Pythagorean Theorem
    • Manipulating Vectors -- adding, subtracting, and resolving
    • River problems
      • Identifying components and resultant
      • Solving
    • Projectiles
      • Vertical motion only -- "free-fall"
      • 2-dimensional motion

Homework: 

• Study.  Make a notes sheet -- at least write down the formulas, even if you don't plan to use the sheet on the exam.  Instead of copying specific problems, write down problem-solving processes (algorithms).

Class 39.5

Warm Up:  1.  How would you find the efficiency of this trebuchet?

2.  How can you find the center of mass of an irregularly shaped object like the one below?

Today:  Determine your trebuchet's efficiency.  Make a slideshow (like this one) showing your process.

1. Energy Input:
   1. Determine the amount of potential energy that is lost by your trebuchet as it launches.  Use the same method that I used in slide 2 of my slideshow.
   2. Create slide 2 of your slideshow.  Include two photos illustrating the change in position of the center of mass of the falling components.
2. Energy Output:  On a desktop or laptop...
   1. Find your video in this Google Drive folder -- The dividing line between 5/6 and 7/8 is somewhere around file number 250.  Note that most file names include an E, but some don't.
   2. Download your video.
   3. Open the Vernier Video Analysis App, and insert your video.
   4. Click "System" and "scale," and then stretch the scale tool to known points on the meter stick in the video.  Enter this distance in meters.
   5. Use the "add" tool to click on the positions of the projectile just before it is launched.  If it's blurry, I find it easiest to click on the front of the blur.
   6. Take a screenshot of your projectile and the blue dots from the vernier app, and paste this into your slideshow on page 3.
   7. Calculate the projectile speed:
      1. Select the Xvelocity and Yvelocity data for these points.  Copy the data.
      2. Open a spreadsheet, and paste the data.
      3. Next to the X and Y velocity columns, create a new column that calculates speed.  You should know how to do this, but ask if you need help.
      4. To determine your projectile's actual speed, you can average the speeds, or you can use the one that you think is probably correct.  Highlight (or make bold) the speed that you are going to use.
      5. Take a screenshot of your spreadsheet calculations, and paste that into your slideshow on page 3.
3. Efficiency.  On slide 4, show your efficiency calculations.

Homework: 

• Review the midterm study guide.  If you have questions, write them down and ask them in class or via email.

Class 39

Warm Up:  Some cultures celebrate a character called Santa Claus, who delivers presents around the world in a sleigh.  This event occurs over a time interval known as Christmas Eve.  If Santa were to deliver a present to every child who believes in him, how fast would Santa need to accelerate between stops in order to deliver all of the presents on Christmas Eve? Santa Claus from an Engineer's Perspective

Today:

• All of the Midterm Exam review stuff is now in Google Classroom.  The only thing I haven't provided is answers to the multiple choice.  Those answers will be available later.  Try the questions first.  You can email me when you want the answers.

• Trebuchet Contest Day Procedure...

  1. Preserve your trebuchet!  After you launch, store it in a safe place, and do not dismantle it.  We won't have time today to find the trebuchets' centers of mass (which we need in order to calculate input energy, and, thus, efficiency).

  2. Record the mass of your projectile + sling.  It should be at least 3 grams.  If it's over weight, you can trim it down with scissors, but it's not clear that this will make a positive difference.

  3. Record the overall mass of your trebuchet (everything but the projectile and sling).

  4. Record the highest height reached by any part of your trebuchet, during the throw.  Do not include the projectile, sling (fishing line), or finger.

  5. Have Mr. Stapleton video your trebuchet throwing its projectile.  This video will be used to determine energy input and energy output.

  6. Have Mr. Stapleton confirm and record your throwing distance.

  7. Enter today's data in this form, so that we can compare preliminary standings.  Bear in mind that overall scores depend on both distance and efficiency.

  8. Store your trebuchet carefully, so that you can finish the analysis after break.

Homework: 

• Review the midterm study guide.  If you have questions, write them down and be prepared to ask them after break.

Warm Up:  Let's discuss the Midterm.

Today:

• Midterm Exam Information (It's all in Google Classroom)

  • Weight:  20% of Semester 1 Grade

  • Format:  100 Total Points -- 25 Multiple Choice (1 point each), 15 Problems (5 points each)

  • Problem Distribution:

    • 1-D Kinematics (3)

    • 2-D Kinematics (4)

    • 1-D Newton's Laws (3)

    • 2-D Newton's Laws (2)

    • Work and Energy (3)

  • More Problem Information

  • Provided Formulas: 

  • Practice Material:

    • Multiple Choice Questions(PDF version) -- 112 questions, 25 of which will appear on the exam. 

    • Problem Review Handout (PDF)  Solutions  Just Answers

  • Links to videos explaining problem solutions are available in Google Classroom.  In fact, everything is in Google Classroom!

• Work time. 

Homework: 

• Optional -- Exam review.  If you complete the multiple choice questions over break, and you want to see my answers before we return to school, email me your request and picture(s) your answers.  I won't be checking my email very often, but if I see your request and answers, I will share my answers with you.  If you have questions about the multiple choice, you may also email me your questions.

Warm Up:  None

Today:

• Optional Test Retake

• Work time -- as quietly as you can

Homework: 

• None

Class 37.5

Warm Up:  

1. How does a hydraulic lift facilitate work with a small input force and a large output force?

2.  How do gears work in a car with a manual transmission? 

Today:

• Work time. 

Homework: 

• None

Class 37

Warm Up:  

1.  What is the point of having a variety of gears on a bicycle? (or a car, motorcycle, etc.)

2.  Why is this effective?

Today:

• Note one more addition to the trebuchet scoring process, dealing with trebuchets that exceed the 0.7J input energy limit.

• Work time. 

Homework: 

• None

Warm Up:  Click this link and answer the trebuchet question for our Physics PLC.

Today:

• Return tests.

• Trebuchet work time

Homework: 

• None

Warm Up:  None

Today:

• Test over work and energy

Homework: 

• None

Class 35.5

Warm Up:  

1.  Which arm ( shown in yellow, in figure 1) will wobble the least on the axle?  Why?

2.  Which arm (figure 2) will experience the least friction as it rotates? Why?

3.  Which arm (figure 3) is least likely to bend the axle?  Why?

Today:

• Work time.  Build your trebuchet

  • Project Guidelines (with two minor updates)  Glue Chuckin' Festival

• Questions about the test?

Homework: 

• Test tomorrow

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:

• Check/review homework 

• Test Concepts and Format

• Trebuchet research and design.

  • Project Guidelines  Glue Chuckin' Festival

  • Some types of trebuchets:

    • King Arthur

    • Floating Arm

    • Fixed counterweight (with wheels)

    • Hinged counterweight

    • Whipper

    • Walking Arm (with example of simple sling)

• B5/6 --Emergency Drill Slide Decks  Fire Egress  Run-Hide-Fight/Resist .  "On slide two of the Fire Egress slidedeck, please emphasize that students should seek the closest exit to leave the building."

• B5/6 -- Questions 5 and 6 on Mr. Pennington's test could be fixed with a simple change. What is the change?

Homework: 

• Test on Tuesday.
• Be ready to start building your trebuchet on Monday.

Class 34.5

Warm Up:  How could we measure the efficiency of this trebuchet?

Today:

• Check/review homework 

• Mr. Pennington's "4 Minute Drill" on page 16.  Answers

Homework: 

• Energy conservation drill (p.16 of packet)  Solutions (I did these quickly, without checkig my work, so it's possible that there are mistakes).

Warm Up:  

Today:

• Check/review homework 

• Project Preview -- EHS Physics Glue Chuckin' Festival

• Test retake time

Homework:  Complete the problem section of Mr. Pennington's 2015-2016 Test on p. 14-15 of the packet.  Solutions

Class 33.5

Warm Up:  

Today:

• Check/review homework 

Homework:  Complete the multiple choice section of Mr. Pennington's 2015-2016 Test on p. 11-13 of the packet.  Solutions

Class 33

Warm Up:  Suppose I hang a spring from the ceiling.  I then hook a 200g mass to the bottom end of the spring and let go.  The mass falls and bobs up and down until it finally comes to rest.  The spring's constant is k = 4N/m.

1.  Does the spring have more total energy at its low point or at its final resting point?

2.  How much work is done by friction during the time the weight is bobbing?

Today:

• Check/review homework

• Notes:  Page 8 -- Other Energy, Electrical Energy Units, Efficiency   Filled-in notes  Video from last year

• Last 30+ minutes -- Test retake time

Homework:  Complete the rest of packet p.9-10 (#4-11, "More work and energy practice problems")  solutions  Video explanations

Class 32.5

Warm Up:  Assuming that all three bows are drawn to a distance of 0.5m...

Today:

• Presentation of Water Rocket Prizes (during 7/8)

• Check/review homework

•  Springs notes (packet page 8)  Notes key

Homework:  Two parts!

1. Complete page 6 (#2 of the practice quiz)  of the packet  Solutions    Video Solutions
2. #1-3 on page 9 (More Work and Energy Practice Problems)  solutions  Problem #3 clarification

Class 32

Warm Up:  

Today:

• Return stuff -- including tests

• Test Retakes:  I will reserve at least 30 minutes at the end of class next Monday and Wednesday, for retakes.  I won't be putting solution videos in Google Classroom, because I think all of the necessary explanation is provided in the homework section of class 30, below.  I did put the answers and solutions in Google Classroom, in the form of a spreadsheet.

• In case you're wondering how all of the tests and projects are being weighted, here's my spreadsheet.

• Unit 5 Packet -- Work and Energy  PDF Version

• Finish the notes on conservation of mechanical energy (pages 2-3)

• Together, work on #6 on page 4. Here's a video explaining #6.

• Begin the homework

Homework:  Complete page 5  of the packet.  Solutions  Video for problem 1  (#1 of the practice quiz)

Class 31.5

Warm Up:  What will happen to kinetic energy, potential energy, thermal energy, and total energy of the skateboarder during a ride in the half pipe?  A) with zero friction  B) with a lot of friction

Today:

• Conservation of energy notes

• A quick "dipstick" question for our physics PLC discussion. Please answer.

Homework:  None

Warm Up:  No warm up -- test today

Today:

• Test

• Start on the homework, if you haven't done it already.

Homework:

• Check last night's homework using the answers below.  If you missed any of them, watch the corresponding part of this video, where I explain my solutions.  We will not go over the homework in class (unless you watched the video and still have questions).

• Homework answers: 1a. 40J   1b. 400W   1c.   21.7m/s   2a.161,040J   2b. 0.49 Snickers   3a.17.8N   3b. 535J   3c.17.7m/s   4. 0.67hp   5a. 604,747J   5b. 201,582W   5c. 270hp   5d. 43.8   5f. 65.7m

• Here are links to the written solutions shown in the video...

  • Answers and solutions to 1, 2, and 5.

  • Solutions to 3 and 4.

 

Class 30.5

Warm Up:  Do you know how to make a cloud in a 2-liter bottle, using water and a small amount of smoke?  Can you explain it in terms of work and energy?

Today:

• Return old tests.

• Begin new unit -- work and energy

• Unit 5 Packet -- Work and Energy  PDF Version

• Notes:  Work, Power, Energy (video from last year's class)

Homework:

• Test tomorrow (Newton's Laws in 2D)

• Work and Energy Practice Problems #1-5 (on p. 3-4 of the packet) -- helpful video

  • Answers and solutions to 1, 2, and 5.

  • Solutions to 3 and 4.

Warm Up:  None

Today:

• Note -- There was a mistake on problem #2, on page 11 of the packet.  I meant to change the coefficient of friction to 0.1.  At 0.3, the system does not accelerate.

• Take tests/retakes

• Work time

Homework:

• Optional -- More Test practice -- packet pages 11-12.  Solutions

  • Problem 1 video

  • Problem 2 video

  • Problem 3 video

  • Problem 4 video

• If you want to re-submit your project sheets, do so by the Tuesday after break.

Class 29.5

Warm Up:  Why does tension show up so often in physics problems?  Is tension overrated and overrepresented?

Today:

• Check/discuss homework

• Does anyone want to start on the Unit 4 test today?

Homework:

• Optional -- More Test practice -- packet pages 11-12.  Solutions

  • Problem 1 video

  • Problem 2 video

  • Problem 3 video

  • Problem 4 video

• If you want to re-submit your project sheets, do so by the Tuesday after break.

Class 29

Warm Up:  

Today:

• Return stuff

• Check/discuss the homework

• (Unit 4 Packet PDF version)

• Do problem #3 on page 6 of the packet.  Solutions to 1-4 on p 5 and 6

• Work time -- practice test.

• If you want to try to take this test early, tomorrow and/or on Friday, you can do that and still have the opportunity to take and retake the test after break.  I should be able to grade it quickly and get it right back to you.

Homework:

• Last year's retake, on pages 7-10 of the packet.  Here's a spreadsheet with the answers.  You can look at the formulas for hints to the solutions.  Written solution to number 3.

• If you want to re-submit your project sheets, do so by the Tuesday after break.

Class 28.5

Warm Up:  

Today:

• Return the project sheets.  I plan to post some more helpful directions tonight. 

• Check and review homework

• Do problem #1 on page 4 of the packet. (Unit 4 Packet PDF version) Video from last year

Homework:

• Complete # 2 from page 5 of the  packet.  Solutions

• If you want to re-submit your project sheets, do so by the Tuesday after break

Class 28

Warm Up:  

Today:

• Turn in project sheets -- one set per group.  All names at the top.

• Test grade distribution

• Get the Unit 4 Packet PDF version.  Number the pages (I forgot).

• Notes -- Bodies on Inclines (packet p 1) -- Video from last year

• Do another example problem (like #2 from the packet)

Homework:

• Complete 1-3 on pages 2 -4 of the unit 4 packet.  Answers and Solutions

Class 27.5

Warm Up:  One end of a rope is attached to the Gladys' belt.  Gladys is pulling directly downward on the other end. Assuming that the pulley and rope are massless and fictionless, how much downward force must Gladys apply in order to ascend?  Gladys weighs 500N.

Today:

• Return tests

• finish the project sheets.

Homework:

• Project sheets are due on Monday.  One per group.

• The optional test retake day is next Friday.

Warm Up:  None

Today:

• Test -- Newton's Laws in 1-D

• You CAN have time tomorrow to finish the project sheets.

Homework:

• Rocket analysis sheets are due on Monday (one set per group).  After your project sheets are graded and returned, your group will get one chance to correct your work and resubmit it for a better grade.

• The optional test retake day is next Friday.

Class 26.5

Warm Up:  The 50kg rower in the photo is accelerating at a rate of -1m/s².  She is pulling against the oars with a force of 100N. Calculate and show all of the forces acting on the rower.

Today:

• Project work time

Homework:

• Test Tomorrow

• Rocket analysis sheets are due on Monday (one set per group).  After your project sheets are graded and returned, your group will get one chance to correct your work and resubmit it for a better grade.

Class 26

Warm Up:   This is a graph of one group's "pressure altitude" data.  The graph shows altitude vs "elapsed seconds."  What do you notice?  Can you explain any of its oddities?

Today:

• If you didn't finish the video analysis yesterday, finish it today.
• As soon as you find your rocket's time aloft, enter it (along with the file name of your video in the Google Drive folder) into this form.
• Complete part 2 of the rocket analysis  PDF version
• If you want to use my correction spreadsheet for #13 and/or #14, here it is.
• You can have project work time today and tomorrow, but we will be starting something new on Friday.  The rocket analyses are due on Monday.  Turn in one set of sheets of paper as a group. 
• Test on Thursday.

Homework:

• Rocket analysis sheets are due on Monday (one set per group).  After your project sheets are graded and returned, your group will get one chance to correct your work and resubmit it for a better grade.

• Test on Thursday -- see class #25 homework for more study materials