Class 76.5 Friday, 5/18/22

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?

 

 

Today:  

Homework:

Class 76.5 Friday, 5/13/22

Warm Up:  

If you're standing next to a race track, what do you hear as the cars pass you?

a.  The cars' pitches change from high to low.

b.  The cars' pitches change from low to high.

c.  There is no change in pitch.

Play this 2020 video for the answer and a discussion of the Doppler Effect.  You can stop it at 2:22 (if you want), because I digress.

 

Today:   Your assignment is to complete the "17.4 Practice" (listed in homework section, below).  In the video I complete number 1 of the assignment, as an example.

  • As a class, watch the first 16:50 of this video (from 2019) explaining the Doppler Effect formula (and how to complete the practice problems).  Stop at 16:50!  You may need to turn up the volume. 
  • You can print the problems from a desktop computer, or just do the work on your own paper.
  • If you want to work on guitar stuff today or in advisory, the cords and amps are in a box lid above the cabinets, on the southmost wall.

Homework: Due on Wednesday

Extra Links, in case you're interested : 

 

Class 76 Thursday, 5/12/22

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?

 

Today:  

 

Homework:

  • 2019-20 Test through problem #4, but skip #7 and #17.  I forgot to include the formula d=rt.  You'll need that one.  [The test is at the end of the handout above] Answers/Solutions

Class 75.5 Wednesday, 5/11/22

Warm Up:   How does a speaker work?

 

Today:  

 

Homework:

  • Magnetism Quiz next Thursday

Class 75 Tuesday, 5/10/22

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

 

Today:  

The rest of the week, and then some (tentative plan):

  • Tuesday (B) -- Project work time. 

  • Wednesday (A) -- Magnetism Quiz Clarity

  • Thursday (B):  Some more sound/waves notes.  Final bit of in-class project work time (30 minutes, at least)

  • Friday (A) -- Wrap up sound/waves concepts

  • Next Monday -- No class, due to testing

  • Next Tuesday -- no class, due to testing

  • Next Wednesday (B day) --

    • Resonance Lab

    • Guitar projects are due

  • Next Thursday (A day) -- magnetism quiz; waves practice test for homework?

  • Next Friday (B day) -- Finish waves.  Waves and Sound test on Tuesday, 5/23. Begin optics?

  • Monday, 5/22 (A day) -- Begin Optics

Class 74.5 Monday, 5/9/22

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?

 

Today:  

Class 74 Friday, 5/6/22

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

 

Today:  

Class 73.5 Thursday, 5/5/22

Warm Up:   Can you break glass with your voice?

 

Today:  

Class 73 Wednesday, 5/4/22

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? 

 

Today:  

  • Make a pickup. Here are the pickup Instructions there will likely be bottlenecks at the winding stations and the soldering stations.  Try to watch someone else do it before you try, and learn from their experience.  If every group does this, the last group should be very efficient and successful.

  • Build your guitar and mark the fret locations.  Here are the guitar directions.  Don't write anything in Sharpie at this point!

Homework:  None

Class 72.5 Tuesday, 5/3/22

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? 

 

Today:  

  • Make a pickup. Here are the pickup Instructions there will likely be bottlenecks at the winding stations and the soldering stations.  Try to watch someone else do it before you try, and learn from their experience.  If every group does this, the last group should be very efficient and successful.

  • Build your guitar.  Here are the guitar directions.  Don't write anything in Sharpie at this point!

Homework:  None

Class 72 Monday, 5/2/22

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

 

Today:  

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

  2. Electric Guitar Project:

  • Get your group on the pickup-winding list.  Then get your bobbin ready so that you can begin winding when your turn comes.  After that, build your guitar (directions below).

  • Make a pickup -- there will likely be bottlenecks at the winding stations and the soldering stations.  Watch the group that goes before you, and learn from their experience.  If every group does this, the last group should be very efficient and successful. [Pickup Instructions]

  • Build your guitar.  Here are the directions.  Don't write anything in Sharpie at this point!

Homework:  None

Class 71.5  Friday, 4/29/22

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?

Today:  

1.  Check/review homework

2.  Begin Electric Guitar Project:

  • Make a pickup -- there will likely be bottlenecks at the winding stations and the soldering stations.  Watch the group that goes before you, and learn from their experience.  If every group does this, the last group should be very efficient and successful. [Pickup Instructions]

  • Pick out (find) a guitar string.  Try to not get poked!

  •  I need to get some more neck materials and hardware, so we won't start on the "body" until tomorrow, but the pickup is the hardest part. 

  • Here's an old one-string electrict guitar that I made in 37 minutes, from start to finish.  It's similar to the one you will make, but I used a tiny neodymium magnet inside the coil.  Your pickup will be simpler.

Homework: 

[This assignment is Google Classroom.]   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.  You will need to use this spreadsheet on Monday, during class.

 

Class 71  Thursday, 4/28/22

Warm Up:   Why does this string look like this?

 

Today:  

Homework: 

#20, on the last page of Notes: Wave and Music theory relating to fret calculations -- and fret practice (pdf version) Solutions

 

Class 70.5  Wednesday, 4/27/22

Warm Up:  

1.  What can we do with these generators?

2.  What do you think is inside them?

Short Video:  Motor vs Generator

Today:  

  • Quiz results (as of 11:30AM)

  • The motor activity is due today.  Submit it in Google Classroom.  If you finish with that, make a speaker (Activity #3). 

  • Pick out (find) a guitar string.  Try to not get poked!

  • If there's time? 

    • Preview the electric guitar project (This is the Physics 100 version, so yours will be a bit different)

    • Instead of a test over electromagnetism, there will be a project (1 string electric guitars) and a quiz.  The quiz will be straightforward, with a tricky bonus section.  Both assignments will be due some time after next week. 

    • See what Chickenbone John can do with a 1 string electric guitar.

Homework: None

 

Class 70  Tuesday, 4/26/22

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

Today:  

  • Check/review the homework

  • Complete Activity #2 in Google Classroom.  If you finish with that, make a speaker (Activity #3).  Try to finish it today.  It's due tomorrow at 2:35PM.

Homework: Complete the "Magnetism Check-In" in Google Classroom.  It won't be graded on correctness -- just completion.

Class 69.5  Monday, 4/25/22

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?

Today:  

  • Return retakes

  • Check/review the homework

  • Complete Activity #2 in Google Classroom.  If you finish with that, make a speaker (Activity #3).

Homework:  

  • Complete #29-39 on p. 12-13 of the packet.  Be aware of a few issues...

    • Fix #30 by changing "leftward" to "rightward."

    • Fix #34 -- assume current to be increasing in magnitude. 

    • For #37, you'll need this PDFto see the diagram. Video explanations  Answers

Class 69  Friday, 4/15/22

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?

 

 

Today:  

  • Test Retake

  •  If you're not taking the test, quietly build a motor (activity #2 in Google Classroom).

Homework:  

Class 68.5  Thursday, 4/14/22

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?

 

Today:  

  • Check/review homework

  • Buzzer videos are due today.  If yours doesn't work, pretend that it does.  You could even make a "BZZZZZZ" sound in the video.  Then explain how it should work.  Don't forget to address everything in the Google Classroom assignment (like explaining the direction of the solenoid magnetic field).  Read the assignment carefully!

  •  Build a motor (activity #2 in Google Classroom).

Homework:  

  • Optional -- prepare for the test retake.  It's tomorrow.

  • Due after break:  Complete #1-28 on p. 9-11 of the packet.  Skip #10 and #19!  They're bad!  Scanned Answers  Video of solutions

Class 68 Wednesday, 4/13/22

Warm Up:  

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

 

Today:  

  • Check/review homework

  • Finish the solenoid buzzers!  Read the video requirements in Google Classroom.  Make your video and submit it.

  •  Start making a motor (activity #2 in Google Classroom).

  • I fixed some of the issues with the Unit 10 Handout PDF

Homework:  

  • #11-12 on page 4 of the packet. 

Class 67.5 Tuesday, 4/12/22

Warm Up:  

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

 

Today:  

  • Return Tests

  • Lenz' Law.  Do some problems together.

Homework:  

  • Complete problems 8-10 on page 4 of the packet

Class 67 Monday, 4/11/22

Warm Up:  

Nonw

 

Today:  

  • Test

  • Here's a copy of the Test bonus.  You can answer it on your own paper and turn it in by the beginning of class tomorrow.

Homework:  

Class 66.5 Friday, 4/8/22

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? 

 

Today:  

  • Check/review the homework

  • Questions about the test?

  • Work time

Homework:  

  • Test on Monday.  For details, see the packet (particularly the practice test) and the link provided in class #56.

  • Due on Tuesday Complete #15-19 on page 6  of the packet   Solutions  Video explanations

Class 66 Thursday, 4/7/22

Warm Up:  

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

 

Today:  

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

Class 65.5 Wednesday, 4/6/22

Warm Up:  

1.  What's wrong with this diagram?

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

 

Today:  

  • Did anyone come up with questions last night?

  • We will go over the circuit lab tomorrow -- because I want to start the new unit today, to spread out the learning a bit.

  • Start the new unit -- Magnetism (and electricity) Unit 10 Handout PDF

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 65 Tuesday, 4/5/22

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?

 

Today:  

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 64.5 Monday, 4/4/22

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

 

Today:  

Homework:  No homework

Class 64 Friday, 4/1/22

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?

 

Today:  

Homework:   Two number twos...

Class 63.5 Thursday, 3/31/22

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.

 

Today:  

Homework:   

  • A7/8 Only -- Complete the Kirchoff's Rules problem that we started in class.  Solutions
Class 63 Wednesday, 3/30/22

Warm Up:  None

 

Today:  

  • Test retake

 

Homework:   

Class 62.5 Tuesday, 3/29/22

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?

 

Today:  

 

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

Class 62 Monday, 3/28/22

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

 

Today:  

Tomorrow: Resistivity and Power (p. 9-10). One resistivity problem.  Here's the problem.  Here's the solution.

Wednesday:  Pennington Practice Test

 

Homework:

Class 61.5 Friday, 3/25/22

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?

 

Today:  

Homework:

  • None

Class 61 Thursday, 3/24/22

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 _____

 

Today:  

Homework: 8 questions spread over 3 separate pages

Class 60.5 Wednesday, 3/23/22

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?

 

Today:  

Homework:

  • No Homework

Class 60 Tuesday, 3/22/22

Warm Up:   None

 

Today:  

  • Test

Homework: Optional Test Bonus:  A single proton and a single electron are released from rest at a distance of 10m from one another.  This happens in the vaccuum of space, far from any electric field or gravitational field.  How long will it take for distance between the proton and the electron to decrease to 5m?  Your answer must be within 0.1s of the exact answer.  [To solve this, I recommend a spreadsheet with a lot of calculating steps.  I used about 15,000 rows of calculations.  You could also use calculus.]

Class 59.5 Thursday, 3/17/22Image result for proton accelerating in an electric field

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?

 

Today:  

Homework: Prepare for the test

Image result for bird on a power lineClass 59 Wednesday, 3/16/22

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?

 

Today:  

  • Test next Tuesday (No school Friday or Monday, so Tuesday is like a Monday.  Don't forget about the test.)

  • Some more test preparation:

    • "4 minute drill"  Drill solutions

    • Test format: 12 multiple choice, 4 short answer (includes electric field drawings and charging by induction), 6 problems

    • Formulas you may need:  You will be given qe, k, and the values of various metric prefixes.

    • Spend some time coming up with a problem-solving algorithm.

    • Charge some conductors by induction, and explain how this charging works, in terms of movement of electrons.

      • Induce a charge on one pie plate using a charged insulator (which can't touch the plate) and a ground (which can touch the plate).

      • Induce charge on two pie plates with opposite charge, using a charged insulator.

Homework:  None

Class 58.5 Tuesday, 3/15/22

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?

 

Today:  

  • Check/review homework

  • A8, finish 18.5 notes.

  • Go over clear tape activity.  Some more tape questions...

    • Suppose you have a stack of three tapes, stuck to a table. 

      • How can you remove them so that two become positive and one becomes negative? 

      • How can you remove them so that one becomes positive and two become negative?

    • What is the charge of tape that's still on the dispenser?

    • What's the charge of a never-used tape roll, right out of the box?

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

Class 58 Monday, 3/14/22

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.

 

Today:  

Homework:  

Class 57.5 Friday, 3/11/22

Warm Up:  

1. What is a spark? Breakdown voltages,

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

spark gap

Today:  

  • Check/review homework

  • Work on tonight's homework

Homework:  

Class 57 Thursday, 3/10/22

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?

Today:  

Homework:  

 

Class 56.5 Wednesday, 3/9/22

Warm Up:  

The deceptively complicated case of the electrified pickle...

Why does the pickle light up Why does it light up on just one end?  Is it always the same end?

 

Today:  

Homework:  

  • None

 

Class 56 Tuesday, 3/8/22

Warm Up:   None

Today:  

  • Optional Test Retake (Circular Motion and Gravity)

  • Work on the homework.

Homework:  

 

Class 55.5 Monday, 3/7/22

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

Today:  

  • Check/Discuss the homework.
  • Electric Field:  Skip the mathematical aspect of electric field for now, and jump right into electric field lines.

Tomorrow's Stuff:

Tonight's Homework:  

Class 55 Friday, 3/4/22

Warm Up:  

1. How does a Van de Graaff Generator Work?

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

Links:

Things to try:

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

Today:  

Homework:  

  • 18.3 Practice (problems 1-5 on packet page 6)  Solutions

Class 54.5 Thursday, 3/3/22

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:  

  • The electrophorus -- how does it work?
  • Check/discuss the homework.
  • The test retake (circular motion and gravity) will be offered next Tuesday.
  • Finish the notes we started yesterday -- polarization
  • Video I made last year, explaining how the Electrophorus works

Homework:  

Class 54 Wednesday, 3/2/22

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: 

Homework:  

 

Class 53 Thursday, 2/17/22

Warm Up: 

None

 

Today: 

  • Test

Homework: 

  • None
Class 52.5 Wednesday, 2/16/22

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 Tuesday, 2/15/22

Warm Up: 

The graphic on the right illustrates the possible scenarios for circle problems.  Sketch or visualize a scenario based on each bullet point.

 

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 anvilSteel 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 Monday, 2/14/22

Warm Up: 

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?  Why? [I believe the height of the loop is around 13m.] 

 

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 Friday, 2/11/22

Warm Up: 

1.  What is a geosynchronous satellite?

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

3.  What is a space elevator?

4.  Assess the supposed manner in which sentient toilet paper rolls hoist themselves to celebrate the new year.

 

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.

Class 50.5 Thursday, 2/10/22

Warm Up: 

According to the diagram on the right...

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.  Why are elliptical foci called foci?  Is anything being focused, and, if so, what and how? 

Today: 

Tentative plan before break:

  • This Friday -- test retake; work time for anyone who isn't retaking the test
  • Monday -- go over practice test #1.  Work on practice test #2
  • Tuesday -- review practice test #2.  Do the "4 minute drill" at the back of the packet.
  • Wednesday --? Maybe some interesting rotational stuff
  • Thursday -- Test over circular motion, gravity, Kepler
  • Friday  -- Return tests.  Maybe some more interesting rotational stuff??
  • Test retake -- Friday, march 4th

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

Class 50 Wednesday, 2/9/22

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: 

Homework: 

Class 49.5 Tuesday, 2/8/22

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: 

Class 49 Monday, 2/7/22

Warm Up: 

1.  Is this an answerable question -- Approximately how fast is the jogger in this video moving?

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

3.  What must move in order for the person to experience simulated gravity... the space station, the person, neither, or both?  What does "move" mean in outer space?

Today: 

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

  • #3 on p.2
  • # 8 on p.3
  • #12-13 on p.5-6
Class 48 Thursday, 2/3/22

Warm Up:  None

Today: 

  • Test

Homework: 

  • None
Class 47.5 Wednesday, 2/2/22

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

Today: 

Homework: 

  • Study for tomorrow's test.
Class 47 Tuesday, 2/1/22

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: 

Homework: 

  • Circular motion problems 1-3 on page 2 of the Unit 7 packet  Solutions
  • Test on Thursday -- be ready.
Class 46.5 Monday, 1/31/22

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 Friday, 1/28/22

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: 

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 Thursday, 1/27/22

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 Wednesday, 1/26/22

Warm Up: 

1.  What's interesting about a Newton's Cradle?

2.  What concepts does a Newton's Cradle demonstrate?

3.  What is the coefficient of restitution for a Newton's Cradle?

 

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 Tuesday, 1/25/22

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

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 (dc) and separation distance (ds) in this scenario.

Today: 

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

Image result for towelClass 44 Monday, 1/24/22

Warm Up: 

How can an understanding of momentum help you turn a towel into a better whip?

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.
Class 43.5 Friday, 1/21/22

Warm Up: 

1.  What will happen if I hold a tennis ball on top of a basketball and drop them to the floor together?

2.  Why does this happen?

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.
Class 43 Thursday, 1/20/22

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

Today: 

Homework: 

Class 42.5 Wednesday, 1/19/22

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

Homework: 

  • None
Class 41.5 Friday, 1/7/22

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
Class 41 Thursday, 1/6/22

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
Class 40.5 Wednesday, 1/5/22

Warm Up:  What is an algorithm?

Today: 

Homework: 

  • Exam prep
Class 40 Tuesday, 1/4/22

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 Monday, 1/3/22

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 Wednesday, 12/22/21

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.
Class 38.5 Tuesday, 12/21/21

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:

    • 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.
Class 38 Monday, 12/20/21

Warm Up:  None

Today:

  • Optional Test Retake

  • Work time -- as quietly as you can

Homework: 

  • None
Class 37.5 Friday, 12/17/21

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?  gearbox-diagram.gif (825×585)How Manual Car Gears Work » Learn Driving Tips

Today:

  • Work time. 

Homework: 

  • None
Class 37 Thursday, 12/16/21

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
Class 36.5 Wednesday, 12/15/21

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

Today:

  • Return tests.

  • Trebuchet work time

Homework: 

  • None
Class 36 Tuesday, 12/14/21

Warm Up:  None

Today:

  • Test over work and energy

Homework: 

  • None
Class 35.5 Monday, 12/13/21

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?

Whic

Today:

  • Work time.  Build your trebuchet

  • Questions about the test?

Homework: 

  • Test tomorrow
Class 35.5 Friday, 12/10/21

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:

Homework: 

  • Test on Tuesday.
  • Be ready to start building your trebuchet on Monday.
Class 34.5 Thursday, 12/9/21

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: 

Class 34 Wednesday, 12/8/21

Warm Up:  

1.  A lightweight object and a very heavy object are sliding with equal speeds along a

level frictionless surface. They both slide up the same frictionless hill.

Which rises to a greater height before coming to rest?

       A) The lightweight object, because it weighs less.

       B) They both slide to the same height.

       C) The heavy object, because it has greater kinetic energy.

       D) Cannot be determined from the information given.

2.  A car and a truck are driving on snow at the same speed and with tires having the same

coefficient of kinetic friction.  They both lock their brakes and skid to a stop on level ground.  If the truck has 2x the

mass of the car, how do their stopping distances compare?

       A) The car slides farther.

       B) The truck slides farther.

       C)  Their sliding distance is equal.

      D) Cannot be determined from the information given

 

Today:

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

Image result for wedge mechanical advantageImage result for hockey stick fulcrumImage result for boat winchClass 33.5 Tuesday, 12/7/21

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.  Which "machine" is fundamentally different? Why?  If you don't have a quick answer to this, move on to the other questions and come back to this one.

2.  Identify the task in each picture.

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

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

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

 

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 Monday, 12/6/21

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:

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

Class 32.5 Friday, 12/3/21

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

1.  Which bow stores the most energy when it is drawn to this distance?

2.  Estimate the energy stored in each bow.

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 Thursday, 12/2/21

Warm Up:  

1.  Can you guess what the "sisyphus train" does?

2.  How did it get that nickname?

 

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 Wednesday, 12/1/21

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:

Homework:  None

Class 31 Tuesday, 11/30/21

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...

  •  

Class 30.5 Monday, 11/29/21

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:

Homework:

Class 30 Friday, 11/19/21

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:

Class 29.5 Thursday, 11/18/21

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:

Class 29 Wednesday, 11/17/21

Warm Up:  

A waiter is delivering a chunk of bone, basted in synovial fluid, to some dinner guests.   Touching only the serving tray (also made of bone), the waiter must deliver the dinner bone to the guests, and place it carefully on their table.  Assuming the guests' table is to our left in the picture, describe what the waiter would need to do in order to make this happen?  Can you sketch the forces on the bone using the head-to-tail method? [Let's just assume that the bone is frictionless.]

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:

Class 28.5 Tuesday, 11/16/21

Warm Up:  

1. Cheryl wants to use some string and a nail to hang a treasured portrait of great-great-grandfather Ernesto as a young man.  The portrait is rather heavy.  Rank the three configurations on the right according to their risk of exceeding the breaking strength of the string.

2. How are static equilibrium and dynamic equilibrium different in physics problems?

 

Today:

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 Monday, 11/15/21

Warm Up:  

A 1kg mass is suspended by a string from the ceiling of a fully-enclosed 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:

  • 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:

Class 27.5 Friday, 11/12/21

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.

Class 27 Thursday, 11/11/21

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 Wednesday, 11/10/21

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 Tuesday, 11/9/21

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

Class 25.5 Monday, 11/8/21

Warm Up:   How many water bottles are used to launch this game show contestant?  Is this for real?

 

Today:

Homework:

  • Work on video analysis calculations.  Compare answers with your group tomorrow.

  • Test on Thursday!

Class 25 Friday, 11/5/21

Warm Up:   None -- rocket launch

Today:

  • Prepare for launching.
    1. Record your rocket's 1) dry mass with sensor and foam, 2) added water volume,  3) overall length
    2. Add water -- carefully.  Pour very slowly from a graduated cylinder.  Clifford Heath's  Water rocket simulator -- seems to underestimate the performance of heavier rockets, but seems to be a good indicator of the best water volume to use.
    3. Optional Sensor Data Collection Plan...
      • Don't put your sensor in your rocket until you're almost ready to launch.  We will have duct tape outside to close up your rocket.
      • Do pay attention to the name on your probe.
      • When you insert the probe, make sure that the button is not getting pressed.  Also, insert it with the positive Z axis facing up (like the picture from yesterday).
      • Once your rocket is on the launcher, remind me to put your rocket in memory data mode.
        • I will connect and confirm that the sensor is collecting data
        • I will start the data logging from my phone.
        • As soon as your rocket lands, bring it to me so that I can stop the data logging. 
        • At this poin turn off the probe to save battery life (hold the button until the LED glows solid red)
      • When you are back in the classroom, connect to the sensor, go to data memory mode, and download the data. BE CAREFUL!!! DO NOT BE A FAST, CRAZY CLICKER or you may clear the data before you realize what you've clicked.  Finally, upload the data to your Google drive and share with your team.
    4. After the launch, clean up the room.  B7/8, please help with the process of packing up the launcher, hoses, and power cord.
    5. If we have time, disassemble your rocket (unless you want to keep it).  Recycle what you can (plastic bottle pieces with no tape and little or no glue).  Return reusable materials (e.g. lead weights, foam, caps, and sensors).  Duct tape, hot glue, and CD parts go in the trash.

Homework:

Class 24.5 Thursday, 11/4/21

Warm Up:   The graph on the right shows the current acceleration data for the PocketLab sensor sitting motionless on my desk.  The positive Z axis (green) extends "perpendicularly" out of my desk surface.  The positive X axis (orange) extends rightward from the sensor.  The positive Y (purple) axis extends away from the camera, parallel to the desk surface.

 

Why are the X and Y axes showing a constant acceleration near 0m/s^2, while the Z axis shows a constant acceleration of around positive 1g?

 

Today:

  • Rocket Project Overview
    • Goal:  Make a rocket that...
      •  flies as high as possible (prize for the highest flyer(s))
      • Allows us to collect data that we can analyze in order to determine the following:
        • Average force of water thrust
        • Time interval of thrust
        • max height
        • drag coefficient
        • and more
    • Data we will collect and analyze
      • Rocket Measurements (Water volume, dry mass, length)
      • Slow motion video
      • Pocketlab Probe Data
        • "Pressure Altitude"
        • "Acceleration"
    • Grading will be based on your analysis of the data, not on rocket success.  You will need to have data to analyze, so your rocket needs to go up straight and come down straight. 
  • Quick demo showing how to collect and save PocketLab probe data in "memory mode." 
  • Finish rocket construction and prepare for tomorrow's launch.
  • Practice collecting data with the probe.  Connect to a probe and insert it into one of our pieces of foam.  Then drop it from the hallway window and record "Acceleration" and "Pressure Altitude" data.  Directions are in this Google Doc -- (pocketlab data collection directions).  Be ready to do this tomorrow when we launch your rocket.  The most important data will be the "Pressure Altitude" data.  If the sensor has less than 50% charge, please charge it.  If you want to compare your data with the real drop distance, the height of the windowsill above the ground outside is approximately 4.5m.
  • PocketLab App Link
  • Record these measurements before tomorrow's launch: 
    • Rocket total dry mass.  This includes everything but the water (rocket, foam, probe, etc)
    • Added water volume.
    • Rocket overall length

Homework:

  • On your own, it would be a good idea to review the packet for next Thursday's test.

Class 24Wednesday, 11/3/21

Warm Up:   No warm-up today.  Make rockets.

 

Today:

  • 7/8 -- we never went over the homework yesterday.  Does anyone have questions?
  • Rocket construction -- important info
    • Design your rocket with recyclability/reusability in mind.  You will have to disassemble it  and sort the parts when we're done.
    • Torch safety:
      • Be aware of objects beyond the end of the torch!
      • Catch all smoke with the fume extractor
      • The nail may still be hot even if it is not glowing red
    • Lead Weights
      • Wash your hands after handling
      • Weights should have a support behind them, in order to prevent their ripping loose during intial acceleration.
    • New group requirement -- no 1 person groups; we need larger groups (at least pairs) to reduct the number of probes that are required.
    • Cutting bottles -- how to start
    • Glue sticks -- location and another warning
    • Duct taping
    • Conserve cardboard.  Cut from a piece that has already been used -- until that piece is used up. 
  • If you're not doing anything else today, you could ractice with a pocketlab probe.  Directions are in this Google Doc -- (pocketlab data collection directions).

Homework:

  • On your own, it would be a good idea to review the packet for next Thursday's test.

Class 23.5 Tuesday, 11/2/21

Warm Up:  [Video link for absent students]The diagram on the right shows a typical water rocket.  Mass has been added to the tip of the rocket, and fins have been added to the back (bottom).  There is a requisite 10cm long section dedicated to holding foam for protecting the probe.

1.  What makes the rocket move upward?

2.  Why do fins need to be added to the back of the rocket?  How does this work?

3.  Why does mass needed to be added to the front of the rocket?  How does this work?

4.  Aside from stability, what other reason is there for adding mass to the rocket?

 

Today:

  • Check/review homework -- I forgot to do this in 7/8!
  • Discuss important rocket design characteristics.  Rocket Guidelines/restrictions
  • Brief rocket planning -- if you want to bring extra materials, assign responsibility
    • Clifford Heath's  Water rocket simulator -- seems to underestimate the performance of heavier rockets, but seems to be a good indicator of the best water volume to use.

Homework:

  • On your own, it would be a good idea to review the packet for next Thursday's test.

Class 23 Monday, 11/1/21

Warm Up:  

Starting from rest, a car in the real world (which includes air) accelerates to its maximum speed, maintains that speed for a few seconds, and then brakes as rapidly as possible.  Draw a series of four force diagrams to show how the net force and the individual forces acting on the car change over time.   Use labeled arrows to show all of the forces (and the net force) acting on the car during each of these time periods.  Draw a diagram for...

1.  The car at rest

2.  The car undergoing initial acceleration

3.  The car at maximum velocity

4.  The car braking

Today:

  • Check/review homework
  • Work Time -- spreadsheet, then practice test

Homework:

  • Complete the rest (p. 26-27) of the practice test in the Unit 3 Packet    answers

  • Finish and submit your spreadsheet and use it to solve this problem...

    • A water rocket has a cross-sectional area of 0.01m and a mass of 0.15kg.  After flying directly upward to a height of 80m, the rocket falls directly downward for exactly 5 seconds before hitting the ground.  If the density of the air in the launch area is 1.22kg/m^3...

      • What is the rocket's drag coefficient?

      • What is the rocket's speed when it hits the ground?

Class 22.5 Friday, 10/29/21

Warm Up:  

1. Which can you throw with more force, a Wiffle Ball® (0.045kg), a baseball (0.145kg), or a shot put (5.45kg)?  Or is there no difference?  Explain your thinking. Some calculations -- don't peek before thinking.

2. What limits the amount of force that you can apply when you throw an object?

Interesting Link:  article about the fastest pitch ever thrown

 

Today:

  • Check/review homework
  • Work Time -- Trajectory with Drag Spreadsheet or homework
  • Deadline change -- spreadsheet is due at midnight on Monday.

Homework:

Class 22 Thursday, 10/28/21

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 a motionless elevator, and then the elevator suddenly began to accelerate downward at 1g?

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

 

Today:

  • Check/review homework
  • Project Overview
    • Design an air pressure-powered water rocket that will fly as high as possible while safely carrying an electronic air pressure probe.  The flight must be controlled (cross-sectional area should be constant) and vertical.
    • Fine-tune a method to collect data that will allow you to do the following:
      • Create a graph of height vs time
      • Calculate the average force of water thrust
    • Use your data and a mathematical model (spreadsheet -- here's my example -- not shared) to determine your rocket's drag coefficient.
    • Calculate (with reasonable accuracy) the number of bottles (similar to your rocket's fuselage) that would be required to launch your body to a height of 10m.  Also calculate the acceleration you would experience.
    • This will be a group project, but parts will be completed individually.
  • Begin work on the mathematical model.  You will be using this for more than just the project, so you must complete your own, individually.
    • Make a copy of this template -- Trajectory With Drag Spreadsheet Template
    • Follow these directions...
    • As you proceed, verify your formulas with these "Solutions" -- which assume that you leave the originally-provided values in the yellow cells

Homework:

Class 21.5 Wednesday, 10/27/21

Warm Up:  

How fast does chalk fall? My spreadsheet answer

Today:

  • Check/review homework

Homework:

Class 21 Tuesday, 10/26/21

Warm Up:  

A parachuter steps out of a plane.  The total mass of the parachuter and gear is 100kg.  After falling for a while, the parachuter reaches a terminal velocity of -55m/s.  A short time later, the parachuter pulls the chute cord and reaches a new terminal velocity of -3m/s.  From that point in time, the parachuter continues to drift to the ground.

Fill out the missing data in the table on packet page 15...

 

Today:

  • Check/review homework
  • Finish the notes -- graph on packet page 14
  • Work Time -- see assignment below

Homework:

Image result for cat falling from buildingClass 20.5 Monday, 10/25/21

Warm Up:  

According to this article, emergency clinic records of 132 cats that jumped from windows of buildings showed a 90% survival rate.  The average drop was 5.5 floors. 

Injuries increased with increasing heights up to 7 floors. When cats fell from over 7 floors, they actually suffered from “less injuries.” 

1. What's going on?

2. What's the rule for deciding whether to use "less" or "fewer?"  Which applies here?

3. When does a falling cat experience zero net force?

4. When is a falling cat a "free-falling" cat?

5.  When does a falling cat experience maximum net force?

 

Today:

Homework:

  • Packet p. 16 -- "Conceptual Practice With Drag"

Class 20 Friday, 10/22/21

Warm Up:  

1.  Explain how a nordic skier can ski forward on level ground with parallel skis (classic style) and without using poles.

2.  Can this be done with downhill skis?  Explain.

Today:

Homework:

  • Multibody Drill A, problems 1-6, on packet pages 11-12.

Class 19.5 Thursday, 10/21/21

Warm Up:   I have a length of treated 4"x4" lumber, some large nails, a hammer, and a large rock.  How will it feel if I put the rock on my head and then have someone pound nails into the wood on top of the rock?

Today:

Homework:

  • On page 10 of the packet, finish writing net force equations for at least two more possible systems.  We will have already finished a few.

 

Class 19 Wednesday, 10/20/21

Warm Up:   None -- retake day

Today:

  • Test retakes, work time

Homework: (continued from yesterday)

Class 18.5 Tuesday, 10/19/21

Warm Up:   On level ground, Tim begins sliding with a velocity of 6m/s.  If Tim's slide lasts for 2 seconds, what is the coefficient of kinetic friction between Tim and the slide?

Today:

  • Check/review homework
  • Work time -- not enough time today for a proper introdu ction to "multibody" problems.
  • The optional retake will be next wednesday

Coming up: 

Homework: Due on Thursday!

Class 18 Monday, 10/18/21

Warm Up:   One way to find the center of mass (a.k.a. balance point) of a stick is to support it with two hands and then slowly move those two hands together until they meet under the stick's center of mass.  Why does this method work?

Today:

  • Classroom culture check-in survey
  • Check/review homework
  • Notes:  Friction (Packet page 8) Filled-in version
  • The optional retake will be next wednesday
  • Work time -- homework or re-do shot one of the launcher project.  It will be a horizontal launch at some height.  No obstacle.

Coming up: 

Homework:

Class 17.5 Friday, 10/15/21

Warm Up:   Why can't you literally "pull yourself up by your own bootstraps?"  This question has also been stated as "why can't you pick yourself up?" 

Today:

  • Return Launcher Contest Problems
  • Check/review homework
  • Notes:  Newton's 3rd Law (Packet page 7) Filled-in notes  video of notes
  • The optional retake will be next wednesday

Homework:

Class 17 Thursday, 10/14/21

Warm Up:   It is possible to remove a sheet paper from under a dry erase pen without touching or tipping the pen.  How can one do this without tipping the pen?  Why does the pen usually fall? 

Today:

Homework:

  • Conceptual #1-2 and Problems #1-6 on pages 4-5 of the Unit 3 Packet  This solution link doesn't seem to be working, so I put the solutions in Google Classroom.  Answers and Solutions
Class 16.5 Wednesday, 10/13/21

Warm Up:   There is a heavy object suspended from the ceiling by a string.  Another segment of the same string is hanging downward from the object.  I am going to pull on the bottom string until one of the two strings breaks.  Which string is going to break first?  Why?

Today:

  • I failed to record some assignments that were due around 9/27 and 9/28.  Who did/didn't do them? (enter grades)
  • Contest Results
  • Did anyone discover any test grading mistakes?
  • Get Unit 3 Packet (Newton's Laws in 1-D)
  • The optional retake will be next wednesday.
  •  Does anyone have questions?

Homework:

  • None -- if you're planning to retake the test, use tonight to prepare.
Class 16 Tuesday, 10/12/21

Warm Up:   Get your launchers ready.  No practice shots!  Make a plan.  Once we get going, we need to achieve less than one minute per shot.  The first shooters can have a little extra time.

Today:

  • Hand in your contest problem solutions.  Make sure that all of your names are on the sheet.
  • Projectile Launcher Contest
  • Return tests.  Be aware that a few students have not finished the test.
  • Test score distribution

Homework:

  • Look over your test and see if you think there were any grading errors.  If you want clarification on a question or problem, watch the corresponding video provided in Google Classroom.  If you think there may be a grading mistake, tell me tomorrow.
Class 15.5 Thursday, 10/7/21

Warm Up:   None

Today:

  • Test, part 2 -- Projectile Problems
  • Work on the contest problems -- due next Tuesday, at the beginning of class.

Homework:

  • Solve the contest problems.  Make a plan for setting up your shots.
Class 15 Wednesday, 10/6/21

Warm Up:   None

Today:

  • Test, part 1-- Conceptual Questions and River Problems
  • Hand out the contest problems.

Homework:

  • Contest problems are due next Tuesday
Class 14.5 Tuesday, 10/5/21

Warm Up:   A boat is following a heading of 56 degrees N of E, and its speed in still water is 1.3 m/s.  Find the velocity of the river's current if the boat's actual velocity (relative to the Earth) is 3.2m/s in a direction 17 degrees W of N. Solution... Video explanation

Today:

Homework:

  • Study
  • Contest problems are due next Tuesday.  Turn in one team copy at the beginning of class and keep the other copy for your own use.
Class 14 Monday, 10/4/21

Warm Up:  Final launcher considerations...

1.  How are you going to aim your launcher in the horizontal plane?

2.  How are you going to aim your launcher in the vertical plane?

3.  How are you going to decide on your projectile's initial height? [Remember that you will be given a vertical "launch window," and it is up to you to determine the exact launch height.]

4.  How are you going to hold your launcher steady, at the height and angle of your choice?

5.  What are you going to do if you take a test shot and it turns out that your distance is off by a large amount?

Today:

Homework:

  • Test on Wednesday and Thursday
  • Do you have questions about anything on the test?  Add your question or request to this Google Doc (as early as you can -- I may not get to late submissions).  I will either create a video answering your question, or I will answer it tomorrow during class.
Class 13.5 Friday, 10/1/21

Warm Up:   Let's try out the PhET Projectile Motion Simulation and see what it has to offer.

The riverboat simulator is also interesting, but I would change the wording a bit.  Can you guess what I would change?

Today:

  • Check/review homework.
  • Final launcher practice -- set up some test shots
  • Hand out the contest problems

Other Stuff

Homework:

  • Study
Class 13 Thursday, 9/30/21

Warm Up:   What's the best way to create a graph like this one?  Exactly what do you need to do?

My spreadsheet

Today:

  • Check/review homework
  • Read over some of the details in the 2nd launcher handout.
  • Launcher calibration and practice

Homework:

Class 12.5 Wednesday, 9/29/21

Warm Up:   I like to start projectile problems by listing important variables in the X and Y dimensions (x and y components of motion).  It might also be helpful to list some resultant variables.  Let's try.

Today:

Homework:

Class 12 Tuesday, 9/28/21

Warm Up:  

1.  Based on the diagram to the right, provide definitions for precision and accuracy.  Which is easier to fix?

2.  Can you suggest some ways to improve precision?  Accuracy?

3.  What are some probable sources of error in your attempts to hit the target?

 

Today:

  • Group size limit change -- groups of 3 are now okay.  You can re-shuffle groups today.  If you want to "make a copy" of your spreadsheet and use that to create a new spreadsheet for your new group, that's okay.  However, if you were one of the group's who had a member who solved the bonus problem, we will need to discuss what makes sense in that case.
  • Get Trajectory Contest Project Handout #2  PDF Version
  • Launcher assembly, modification, data collection, and calibration graph creation.
  • Launcher Parts:    What to save in your Ziplock bag...
  • If your spreadsheet calculators don't work right now, record your calibration data anyway.  Then fix your spreadsheet and figure out the intitial velocities later.
  • Store your plunger/bands, projectile, and trigger/string in a Ziplock bag with your names and block on it.

Homework:

Class 11.5 Monday, 9/27/21

Warm Up:  

The diagram on the right shows the trajectory of a free-falling projectile that was launched horizontally.  Sketch the diagram.  Show/label the projectile's overall velocity (v), x velocity (vx), and y velocity (vy) at the start of its flight and at some other point in the flight.

Today:

  • Return retakes -- Reflect on 1st Unit, now that you've been through a full unit cycle.
  • Check/Review Homeworks
    • Projectile trajectory answers
    • Pennington practice test

Homework: Finish any homework that you didn't complete for last class (including the projectile launcher practice problems -- p. 15; and Mr. Pennington's practice test -- p. 10-15)

 

Class 11 Friday, 9/24/21

Warm Up:  

None -- test retake day

Today:

  • Retake
  • Work time -- Project stuff or Mr. Pennington's old Chapter 3 Test (page 10-14 of the Unit 2 Packet Solutions 

Homework:

Class 10.5 Thursday, 9/23/21

Warm Up:  

Find a combination of initial angle and initial speed that will carry a projectile from the launch point to the target (assuming no air resistance).

You can guess, and I will check, with my private spreadsheet. :-)

Today:

  • Clarify the homework assignments.
  • Work time.  Complete your spreadsheet and then use Sheet 1 to complete the projectile practice problems on p. 15 of the packet.
  • Test retake tomorrow.  If you're not retaking the test, you can work on Mr. Pennington's old test (p. 10-14)

Homework:

  • Use Sheet 1 of your spreadsheet (or a copy of it) to complete the Projectile Launcher Spreadsheet Practice Problems on p. 15 of the Unit 2 Packet.
  • Sheets 1 and 2 of your group's trajectory spreadsheet are due by Monday.  At least one of you should submit the spreadsheet in Google Classroom.
Class 10 Wednesday, 9/22/21

Warm Up:  

1.  Based on the existing pattern, what should number should appear in the 7th row of column C?

2.  If we wanted to continue that pattern quickly and easily, how could we set up a spreadsheet to do it?

 

Today:

  • Please answer this brief multiple choice question (for our Wednesday afternoon teacher meeting).  Thanks!
  • Check/review homework
  • Trajectory Project:
    • Get Trajectory Contest Project Handout #1 PDF Version
    • Find a partner.
    • Modify this spreadsheet template to create the Sheet 1 ("Trajectory") of your Trajectory Project spreadsheet.
    • As you build your spreadsheet, use this screenshot to check your work.  Keep the yellow cells the same as mine so that you can use my calculations to verify yours. .  I plan to make a video during class and then make the video available on my YouTube channel.
    • FYI, here are what Sheets 2 and 3 will look like...
      • Sheet 2 (Launcher Calibration)
      • Sheet 3 (Launcher Calibration Graph)

Homework:

  • Divide tasks and work on the project at home.  Before class on Monday, you should be finished with Sheet 1, as well as the initial velocity calculators on Sheet 2.  Hopefully, you will calibrate your launcher on Monday (split block) and Tuesday. 
  • Test retake on Friday. 
Class 9.5 Tuesday, 9/21/21

Warm Up:   Sketch a head-to-tail diagram for each of the following.  We will look at the graphical solutions afterward.

1.  A baggage conveyor is moving in a direction 25 degrees South of East at a rate of 1.5m/s.  A bug riding on the conveyor has a velocity of 2m/s in a direction 30 degrees East of South.  What is the bug's heading and "speed on a still conveyor?"

2. A river's 3mph current flows in a direction 15 degrees West of North.  A swimmer, whose speed in still water is 2m/s, swims across the river with a heading 35 degrees South of West.  What is the swimmer's velocity, relative to the Earth?

3.  A superhero steward on an airplane is traveling in a direction 10 degrees East of South, and their speed is 580mph.  The plane's velocity is 460mph in a direction 5 degrees West of South.  What is the steward's heading and their "speed on a still plane?"

 

Sketches and answers: ---Argh!! #1 is wrong!  But 2 and 3 are right.

 

Today:

  • Update seating chart in A8
  • For even more non-orthogonal river problem practice, see the warm-ups from last year's classes #20 and #21.  A link to a video solution is included after each warm-up.
  • Tpmorrow:  Modify this spreadsheet template to create a mathematical model of a projectile's trajectory.  Make your own copy of the template.  Then use formulas to create the spreadsheet. .  I plan to make a video during class and then make the video available on my YouTube channel.
  • Check/review homework.

 

Homework:

  • Projectile Practice Problem #3 on p. 9 of the Unit 2 Packet Solutions
  • Don't forget that your chance to retake the test is on Friday.
Class 9 Monday, 9/19/21

Warm Up:  Suppose you shoot a projectile, horizontally, from the edge of a school tabletop that is 0.95m above the floor.  If the projectile hits the floor at a distance of 14 floor tiles from the table...

a.  What is the projectile's v0?

b.  How would you find the projectiles' final speed?

c.  How would you find the  angle at which the projectile hits the floor?

 

Today:

Rest of the week (tentative plan):

  • Tuesday -- create a trajectory spreadsheet
  • Wednesday -- begin trajectory contest project
  • Thursday -- continue project work
  • Friday -- test retake opportunity; Mr. Pennington's Unit 2 practice test

 

Homework:

Class 8.5 Friday, 9/17/21

Warm Up:  

1.  What do "air speed" and "speed in still water" mean?

2.  What is a "heading?"

3.  Let's practice resolving non-orthogonal vectors into their x and y components.

Identify the component and resultant vectors for the following "river problems."  Then sketch them using head-to-tail vector addition.

3.  A boat travels eastward at a rate of 3m/s.  The boat's heading is northeastward, and the boat's speed in still water is 8m/s.  What is the velocity of the water in which the paddler is paddling?

4.  A quadcopter has a velocity of 20m/s westward.  The wind is blowing southward at a rate of 10m/s.  What are the quadcopter's airspeed and heading?

5.  The driver of a golf cart on an aircraft carrier uses a compass to head northward.  The cart's speedometer reads 10mph.  The aircraft carrier's heading is eastward, and its speed in still water is15mph.  The ocean current is northwestward at a rate of 5mph.  What is the actual velocity (relative to the Earth) of the golf cart?

 

 

Today:

Homework:

  • River Problems 5-6.  These are non-orthogonal.  Solutions
Class 8 Thursday, 9/16/21

Warm Up:  

An airplane flying horizontally with a ground speed of 120 m/s releases care packages from a height of 4,800 meters.  If the packages are not affected by air resistance, how far ahead of the target (in the x dimension) should the packages be released?

 

Today:

Homework:

Class 7.5 Wednesday, 9/15/21

Warm Up:  

1.  Suppose the two vectors on the right represent two forces acting on the clam.  In what direction will the clam accelerate?  How will that acceleration compare to the accelerations we would observe if each force were acting alone?

2.  The diagram on the right shows a top view of a train car that is moving at a rate of 2m/s.  You are in the car.  In which direction and how fast should you walk in order to have the intended velocity shown on the right.

 

Today:

Homework:

  •  None
Class 7 Tuesday, 9/14/21

Warm Up:  None

Today:

  • Test

Homework:

  • None
Curling Technique — Curling — Jonathan HavercroftClass 6.5 Monday, 9/13/21

Warm Up:  How can we find the acceleration of an object as it slides across this floor, using only a stopwatch and the floor as measuring devices?

Today:

  • Check/review homework.
  • Interests of students in my two classes:
  • Questions about the test? -- Did anyone notice any more mistakes?
  • Here's a mostly nonsensical problem for the people who want to think about time travel...

If you could travel in time, and if you found yourself in the infinite loop of acceleration changes shown below... would you ever find yourself in the same location as another past self?  Explain by creating analagous graphs of velocity and distance vs time.

Homework:

  •  Study -- Hopefully you have been marking items in the notes and homework that were tricky the first time.  Go back and quiz yourself over those items.  They should no longer be tricky.  If they are, get help.  Memorize the formulas if you want an extra point. Kinematics formulas Quizlet
Class 6 Friday, 9/10/21

Warm Up:  

1.  Create a kinematics problems (on your own, or as a class).  Start by listing the available formulas and/or variable.

2.  If we graphed the motion of a vertically-launched projectile, which of these graphs would have at least one sharp corner in it? 

a. velocity vs. time    b. speed vs. time    c.  position vs. time    d. acceleration vs. time 

e. none of these    f. all of these

Today:

More Kinematics Practice (optional!)

  1. New questions and problems, based on form feedback...
    1. Extra Unit 1 Test Practice -- Questions and problems
    2. Extra Unit 1 Test Practice -- Answer Key The answer to #5 on the first section was wrong.  It should be correct now (if it's highlighted in yellow).  Solution to Extended Kinematics Problem
  2. Optional -- Here is some more practice creating graphs for events
    1. Blank PDF Handout -- "Extra Graphing Practice"
    2. Solutions(**On my graph of position vs time for the soccer ball kick, my graph should really have started and ended at the same position.)
    3. Video of me working through these and creating solutions
  3. Optional -- More practice with simple (one formula required) kinematics problems.  Make your own copy and expand column D to see the answers.

Homework:

  •  "Classic River Problem" on page 4 of the Unit 2 Packet.
Class 5.5 Thursday, 9/9/21

Warm Up:

Sketch a graph of acceleration vs. time for a suction cup Nerf dart that is shot at a wall.  Start your graph just before the dart begins to move, and end it just after the dart stops.

Today:

  • Check/review homework.  Improving our troubleshooting efficiency.
  • Pinpoint weaknesses.
  • Test on Tuesday:  42 points total
    • 16 multiple choice / short answer -- 1 point each
    • 1 unit conversion -- 2 points
    • 4 Problems -- 4 points each
    • Extended Problem -- 5 parts, worth 2 points each
    • Bonus (optional) -- 1 point if correct
    • 1 point for opting out of the formula sheet.
  • Fill out this form if you want to request extra practice.

Homework:

Class 5 Wednesday, 9/8/21

Warm Up:

Mr. Chase pointed out that there are 9 types of motion.  This is based on the fact that Velocity can be +, -, or 0, and acceleration can also be +, -, or 0.  A pendulum swinging back and forth demonstrates 8 out of these 9 types of motion.

1.  Graph the pendulum's X velocity over one full period (over and back) of motion.

2.  Identify where in the video each of those 8 types of motion occurs.

3.  Which of these 9 types of motion is not demonstrated?

 

Today:

Homework:

Class 4.5 Tuesday, 9/7/21

Warm Up:  Simplify this "extended" kinematics problem by drawing a diagram and identifying intervals with unique accelerations and or unique initial/final conditions.  You don't have to solve the problem.

A ball is dropped (in free-fall) from a height of 16m. When it reaches a speed of 3m/s, the ball contacts a compression spring.  The ball continues downward, slowing down as it compresses the spring and then speeding up as it is thrown back upward by the spring.  For purposes of calculation, you can consider the ball to experience a constant +35m/s2 acceleration during its 0.15 seconds of contact with the spring. 

1.  What is the height of the ball when the spring is fully compressed?

2.  What is the maximum height of the ball after it leaves the spring?

Today:

Homework:

Class 4 Friday, 9/3/21

Warm Up:   

1. Suppose students enter our school at a rate of 54 pounds/sec (pounds of student).  After they enter, they lie down,  head-to-toe, forming a line whose length is the sum of their heights.  Since an average 16 year old student's weight:height ratio is about 2.07 lb/in (and assuming these are all average students with that ratio), how many days will it take them to form a line 3 miles long?

2.  Is this actually a "possible problem," in the sense that it could happen and that it is solvable given the information above?

Today:

  • Warm-up -- discuss how dimensional analysis works.
  • Check/review homework
  • Spool tractor challenge -- accuracy and speed

Homework:

Class 3.5 Thursday, 9/2/21

Warm Up:

Consider the case of this ball.  At t = 0s, the ball is free-falling directly upward at a height o 10m, with a speed of 20m/s.  Sketch graphs of the ball's position, velocity, and acceleration (vs. time) over the next 4 seconds. [For simplicity, use g =10m/s2 instead of g = 9.8m/s2]

Today:

  • Check/review homework
  • Spool tractor practice

Homework:

  •  Complete the problems section of Mr. Pennington's Old 1-D Kinematics Test (Packet page 20). **Note that problem 1 is a unit conversion problem, which we haven't been over in class (though you should be well-versed in unit conversions from Chemistry).  You will have a chance to practice unit conversions if you want more practice.  And in problem #2 you'll need to know that circumference = pi*d.  Here's the Answer Key. If you have questions, watch this Video for Help with the Problems
Class 3 Wednesday, 9/1/21

Warm Up:

1. For letter a, on the right describe what an object could be doing in order to have both positive velocity and positive acceleration.

2.  Do the same for the rest of the letters.

 

Today:

Homework:

  •  Complete the rest of the multiple choice on Mr. Pennington's Old 1-D Kinematics Test (Packet pages 18-20).  Answer Key. If you have questions, watch this Video for Help
Class 2.5 Tuesday, 8/31/21

Warm Up:  What is a spool tractor?  How does one work?

Today:

 

Homework:

  • Complete Multiple Choice 1-12 from Mr. Pennington's Old 1-D Kinematics Test (Packet pages 17-18).  Answer Key. If you have questions, watch this Video for Help
Class 2 Monday, 8/30/21

Warm Up:

1.  Assuming that the man in the picture is 2m tall, and the frame rate of the camera was the usual 30 frames per second, what was the approximate maximum speed of the object?

2.  Based on your answers, do you think the assumption of 30 frames per second was too low, too high, or about right?

Today:

Homework:

Class 1.5 Friday, 8/27/21

Warm Up:

Use the velocity vs time graph on the right to sketch the shape of a corresponding position vs time graph.  [Assume that motion away from the sensor is positive, and motion toward the sensor is negative.]

Today:

Optional Reading -- Online Textbook:

Homework:

Class 1: Thursday, 8/26/21

Warm Up:  Suppose you're involved in a 2 lap race.  If you want your overall average speed to be twice as fast as your speed for the first lap, how much faster do you have to go during the 2nd lap? [To calculate average speed you can use rate = distance / time]

Today:

Optional Online Textbook Reading:

Homework:

Class 0.5: Wednesday, 8/25/21

Physics 200: Mr. Stapleton

Warm Up:

Spin one of the "sprotating cylinders" by pressing one end until it squirts out from under your finger.  Try pressing the other end.

When the cylinder is spinning, why do you only see the symbol that you press?

Slow motion

Today:

Links:

Online Textbook Reading:

Homework: None