Class 40: Monday, 6/6/26

Warm Up: 

1.  Someone drops a Frisbee from table height.  At the same time, someone throws a Frisbee horizontally at table height.  Which one hits the ground first?  Why?  How does this relate to the variable speed along the length of a river that is in equlibrium?

2.  "Frisbee" should really have a trademark symbol, but my software doesn't offer one.  Who owns the trademark, and where did the name come from?

3.  In order to talk about disc throws, you need to be able to identify the fast side of the disc and the slow side of the disc.  Which is which?

4.  You can make the disc curve left or right with either an "inside-out" or an  "outside-in" throw.  What's the difference, and why does one tend to curve more?  What are some other applications of the Magnus Effect?

5.  A common embarrassment in disc throwing happens when the disc "rolls over" in the air, hits the ground, and rolls in a circle nowhere near the thrower's target.  The direction of the roll is predictable.  When an ultimate disc rolls, which side lifts up (assuming it's right-side-up to begin with)?

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

Today:  

  • 5/6 -- return magnetism quizzes
  • Return electricity retakes and other stuff
  • Final exam review -- questions?  Requests to work through problems?
  • Other options -- "Just One," "Reverse Charades," singalong, Ultimate
  • Say goodbye to seniors!

Homework:  

  • Prepare for the final exam -- or summer.
Class 39: Thursday, 6/4/26

Warm Up: 

1.  What's the relationship between wavelength and frequency (wave cycles per second)?

2.  Unless you change the tension, the speed of a wave traveling along the length of a guitar string is constant.  Do waves really travel along the length of guitar strings?  [Walter Fendt's Standing Wave Simulation]

3.  In music, how does the frequency of any note compare to the same note one octave above? [Online Tone Generator] 

4.  Into how many parts do we ["western music" composers and listeners] divide an octave?  [Online Piano Keyboard]

5.  By what factor is frequency multiplied if you jump up in frequency by an interval of 2 octaves?  3 octaves?  4 octaves? 1/12 of an octave?

6.  How does the distance between one guitar fret and the guitar's saddle compare to the distance between the next fret and the saddle?

Today:  

  • Final exam review -- questions?  Requests to work through problems?
  • Electricity test retake
  • Continue guitar making

Homework:  

  • Prepare for the final exam -- or summer.
Class 38: Tuesday, 6/2/26

Warm Up: 

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

1.  What does a transformer do?

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

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

 4.  Interesting Veritasium video about Faraday's discoveries and "levitating barbecue."

Today:  

  • Magnetism Quiz -- Drop it if you don't like it.
  • Final exam review -- questions?  Requests to work through problems?
  • Work time

Homework:  

  • Prepare for the final exam -- or summer.
  • Optional test retake next class
Class 37: Friday, 5/29/26

Warm Up: Are these generators, motors, or both?  How can you prove it?

Today:  

  • Mr. Stapleton's goal for the rest of the year -- focus on keeping it fun and not making things too complicated.
  • Return tests
    • If you want to retake the electricity test, you can retake it in class next Thursday or outside of class beginning on Monday.  It will be broken up into the following sections:
      • 1) Page 1
      • 2) Flashlight circuit -- problem 2
      • 3) Simple problems -- problems 1, 3, and 4
      • 4) Solving circuits -- problems 5, 6, and 7
      • 5) Kirchoff's Rules -- problem 8
  • Check/review homework
  • The last bit of magnetism -- Lenz's Law:   Unit 9 Handout Part 1 (PDF) Answer Key  If we need to break up the monotony...
  • Sadly, there's just not time for a proper electric guitar project, but if you want to make an electric 4 or 6 string fretted instrument (wind the pickup, set up the frets, and play) let me know today (email or in person) and try to sign up for my FLEX next week.  We will probably have some class time for it, too.
  • Final Exam Stuff:

Homework:  

  • Quiz next class (Tuesday) over magnetism.  You can drop it if you don't like your score.
  • Prepare for the Final exam.
Class 36: Wednesday, 5/27/26

Warm Up: None

Today:  

  • Test
  • Get the final exam review. 

Homework:  
Class 35: Friday, 5/22/26

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

Today:  

  • Check/review homework
  • Continue Unit 9:  Electric Guitars (magnetism and waves) Unit 9 Handout Part 1 (PDF) Answer Key
    • More right hand rule (with curved fingers) practice
    • New right hand rule with straight fingers and force! -- and practice
    • Lenz's Law -- and practice
  •  Generators and Motors are the same things in reverse (check out the Genecons)
  • electric motor video

Homework:  

  • Test Wednesday
Class 34: Wednesday, 5/20/26

Warm Up: If these two bulbs are wired to the battery in series, one of them is brighter.  If they are wired in parallel, the other one is brighter.  Which is brighter in each case?  Why?

Today:  

  • Check/review homework
  • Review answers to Circuit Practice Lab (pdf) PhET presets link
  • Begin Unit 9:  Electric Guitars (magnetism and waves) Unit 9 Handout (PDF) Answer Key -- See Video
  • My primary goals for the E&M part of unit 9:  you will (hopefully)...
    • know enough to be able to make simple electric motors (devices to push things) and generators (devices to create current by pushing things). 
    • understand how electric field, current, and magnetism are related.
    • understand the basic working principles behind wireless charging, induction stoves, and magnetic pickups

Homework:  
Class 33: Monday, 5/18

Warm Up: 

1.  What happens when you electrocute a kosher dill pickle?  Why?

2.  What are its V, I, R, and P?  When?

Basic explanation

More nuanced explanation -- I'm becoming skeptical of this one, but I think it has some good ideas.

Street lamps

Today:  

Homework:  

 
Class 32: Thursday, 5/14

Warm Up: 

Suppose you wired a 10W LED bulb and a 2hp  table saw (appx. 1500W) on the same 120V circuit in your house.

1.  Are household circuits wired in series or parallel?

2.  Calculate the resistance of each item.

3.  What would happen if you wired these items in the other circuit configuration?  Why?

4.  What determines the amount of current that will flow through a circuit? [We didn't address this in our models.]

Today:  

Homework:  Multiple choice section of the Electricity Practice Test at the back of Electricity Handout 3 (pdf)
Class 31: Tuesday, 5/12

Warm Up:  None

Today:  

  • Test retake
  • Work time

Homework:  
Class 30: Friday, 5/8

Warm Up:  Find the currents in this circuit.

Today:  

Homework:   Due next Thursday

  • 3/4 and 5/6 -- Complete the "9 companions" -- p. 14
  • 1/2 and 3/4 Fill out data tables for all of the circuits on P. 15-16 Solutions
  • Optional -- Prepare for the test retake on Tuesday.
Class 29: Wednesday, 5/6

Warm Up:  What happens when you touch some steel wool to opposite electrodes of a 9V battery?  Why?

Today:

  • Return tests.  Here's the distribution so far
    • What happened? -- that is mostly a question for you to ask yourself.
  • Check/review homework
  • Together -- do the first 2-Battery Kirchoff's Rules Problem on p. 6.
  • Get Unit 8 Handout Part 2 (PDF) -- **Make this change on p.11 -- Change the 3W device to 27W and change the 1W device to 9W.
  • Continue notes -- possibly jump to circuit reduction rules for series and parallel circuits.

Homework:  

  • The last Kirchoff's Rules Problem -- on p. 6.  solution
  • B1/2 only -- The "9 companions" -- page 14 of the new handout. 
Class 28: Monday, 5/4

Warm Up:  None

Today:

  • Interest in Ultimate at Hornet Hullaballoo?
  • Test

Homework:  

  • Problems on P.4-5.  Follow along with this video to complete the problems on p. 4 and the top of p. 5.  Then complete the problem on the bottom of page 5 on your own.  If you need help with the bottom problem, follow along with me in this video.  Unit 8 Handout -- Electricity (PDF)
  • Optional: If you want to try page 6, here are the solutions.  I will probably assign these later.
Class 27: Thursday, 4/30

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 (R) is like _____

4.  What creates voltage?

 

Today:

  • Check/review individual practice test.
  • Check your slideshow to make sure everything is shared with me.  If it's not, share it, but please don't send a notification.
  • Return and sort car parts.
  • Group Test Corrections due today
  • Begin new unit:

Homework:  

  • Test on Monday
Image result for dry limbs firewood driftwoodClass 26: Tuesday, 4/28

Warm Up: 

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

Today:

  • Awards Presentation -- Contest Results
  • Newly-Updated Deadlines:
    • Today:  work on Slideshow (details in Google Classroom)  If you're missing some things -- like coefficient of friction, top speed, max energy -- I will help you get those quickly at the beginning of class on Tuesday after break.
    • Thursday --
      • Check/review individual practice test
      • Car disassembly and parts return
      • Group Test Corrections due
      • Begin new unit?
    • Monday -- Individual Test

Homework:  

Class 25: Friday, 4/15

Warm Up: 

1.  Briefly review how to measure your top speed  (warm up from class 19). 
2.  If you can't get your car to go straight, you can glue a 3-d printed part to it to make it follow a line.  For parts of your car that are farther than 1cm from the floor, you'll need to add some extension material.

Today:

  • Updated Deadlines:
    • Group Test -- Due last class -- don't let your car accelerate until you've submitted it.
    • Speed Measurement For Contest -- Today
    • Slideshow (details in Google Classroom) -- Tuesday after break.  If you're missing some things -- like coefficient of friction, top speed, max energy -- I will help you get those quickly at the beginning of class on Tuesday after break.
    • Group Test Corrections -- Thursday (4/30) after break -- before 8:40AM
    • Individual Test -- Like the group test, but individual -- Thursday (4/30) after break
  • Slideshow assignments have been added to Google Classroom

 

Homework:  

  • Finish slideshow on Tuesday after break
  • Individual test on Thursday after break
Class 24: Wednesday, 4/15

Warm Up:  None -- to allow more work time

Today:

  • Updated Deadlines:
    • Group Test -- Today
    • Speed Measurement For Contest -- Friday
    • Slideshow (details in Google Classroom) -- Tuesday after break
    • Group Test Corrections -- Thursday (4/30) after break -- before 8:40AM
    • Individual Test -- Like the group test, but individual -- Thursday (4/30) after break
  • Slideshow assignments have been added to Google Classroom

 

Homework:  

  • None
Image result for quadcopter controlsClass 23: Monday, 4/13

Warm Up: 

A quadcopter has four propellers that usually alternate in their directions of rotation.  The diagram on the right explains how movements are controlled. 

  1.  How does conservation of angular momentum enable this quadcopter to achieve a yaw?  Why do all four motors have to change their speed -- couldn't yaw be accomplished with just one?
  2.  In order to pitch or roll, why can't one motor just speed up (without the opposite motor slowing down)?

Today:

Homework:  

  • Work on the group test calculations.  They're due on Wednesday.
Class 22: Thursday, 4/9

Warm Up: 

  1.   How do falling cats always manage to land on their feet?
  2.   They do it by somehow changing their angular position without changing their angular momentum.  How can we simulate this with the turntable?
  3.   Why wouldn't a linear version of this work? Why can't you change your linear position without changing your linear momentum?  What would a linear version of this look like?

Today:

  • Get your measurements and calculations done today.  Understand what you're doing.  You will all, individually, have to do this on the individual test.
  • Important Notes:
    • DO NOT LET YOUR CAR ACCELERATE FOR MORE THAN ONE FOOT.  You can learn everything you need to know in order to maximize your car's speed without actually letting it accelerate.
    • It might be wise to find your rear wheel and axle MOI using the Idisk = 1/2mr2 method.  You need an accurate MOI to get an accurate energy measurement, so that you can get an accurate velocity prediction.
  • Complete the "Group Test".  It's open-note and takehomeable, by the way. Work through steps 3-8 of the  in the Instructable, and enter your your data and calculations in to the spreadsheet.

Homework:  

  • Work on the group test calculations.  They're due by the end of class on Monday.
Class 21: Tuesday, 4/7

Warm Up: 

1.  The formula for linear momentum is p=mv.  Guess the rest of the formula for angular momentum.  The symbol for angular momentum is L.  L = ?

2.  Guess what the Law of Conservation of Angular Momentum states?

3.  Use the Law of Angular momentum to explain how figure skaters can spin so fast.

Today:

  • Assemble cars
  • Work on the "Group Test" -- See details in Google Classroom.

Homework:  

  • Work on the group test calculations.  They're due by the end of class on Monday.
Class 20: Friday, 4/3

Warm Up:  Rubber Bands Can Be Perplexing...

1.  Suppose an 8N force is required to stretch a single, ordinary rubber band a distance of x = 20cm.  The band (labeled A in the diagram) is 10cm long before it is stretched.  How far must the other configurations be stretched in order to reach the same tension of 8N? [Assume that the rubber bands behave like ideal springs with a constant k.]

2.  Assuming that the bands are 100% efficient, which one stores the most energy when they are all stretched to a tension of 8N?  Which stores the least?

Configuration: Stretch Distance To Reach 8N (m) Energy Stored In Bands (J)
A.  Standard rubber band -- 2 strands 0.2  
B.  2 rubber bands in "parallel":    
C.  2 rubber bands in "series"    
D. 1 rubber band, cut and laid out as a single strand    

Today:

  • Check/review homework
  • Review the rubber band car contest rules (PDF)
  • Take a look at the car part data sheet.  You can use it to estimate your car's mass before you order the parts.  You can also use it to calculate moments of inertia.
  • Use this form to place your order for frames, wheels, and other materials
  • Here are some more parts that people have asked for -- available to anyone upon request.
  • Finish the lab from last class.
  • Start creating your rubber band motor design.  Now that you know how long your frame will be, you can begin building your motor.  We can measure coefficients of friction so that you have an idea of how much force your motor can apply.

Homework:  

Class 19: Wednesday, 4/1

Warm Up:  Use the 240fps video in Google Classroom to find the average velocity of this car as it crosses the designated "finish interval."

Today:

Homework:  

Class 18: Monday, 3/30

Warm Up:  Use the 240fps video in Google Classroom to calculate the rubber band energy output of a car.

Today:

Homework:  

Class 17: Thursday, 3/26

Warm Up: 

A sphere, a cylinder, a thin hoop, and a frictionless box are released from rest at the top of ramp.  Their masses and heights are identical.  There is no air resistance, and all of the round objects roll smoothly, so there is no kinetic friction. 

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

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

3.  How would the results be different if some objects had more mass or greater size than others?

4.  How would the results be different if the ramp itself were frictionless?

5.  What type of object would roll faster than any of these round objects?

Today:

  • Check/review homework
    •  
  • Unit 6 Handout #2 (pdf):  Torque and Rotational Inertia (a.k.a. MOI).  The goal here is to organize some of the concepts -- since we just "jumped in" to the car calculations.
  • Energy problem practice
  • Finish the MOI lab from last class. 
  • Finish cars.  Add motors.

Homework:  

  •  Momentum test retake option next class.
  • #3 on page 4 of the new handout  Unit 6 Handout #2 (pdf  -- Here's the solution..
Class 16: Tuesday, 3/24

Warm Up: 

Suppose you're trying to balance a meter stick vertically, as shown in the picture.
1.  How might attaching a heavy c-clamp to the meter stick affect your balancing success?
2.  Where should you put the clamp, and where should you not put it (if you want to make balancing easier)?
3.  How/why does this work?

**Listen to the beat demonstrator?

Today:

  • Energy Reretakes are ready
  • Check/review homework
  • Finish the moment of inertia calculations (steps 9-14; skip 6-8, since they don't help calculate MOI)
  • As a group -- calculate your rear and front moments of inertia.  Turn in your calculations to this spreadsheet.
  • Important Dates:
    • Friday, 4/3 -- submit requests for new wheels and frames
    • Tuesday, 4/7 -- assembly of new cars.  Begin group test.
    • Thursday, 4/9 Finish group Test -- predicting your car's top speed
    • Monday, 4/13 -- Contest.  Return group test for corrections
    • Friday, 4/17 -- Individual test

Homework:  

Class 15: Wednesday, 3/17

Warm Up: 

A force is a push or a pull.  A torque is the rotational analog of force.  It's a twisting/rotating force...

1.  What are some other rotational rotational versions of the linear quantities we have been using?

2.  During this unit, sometimes "rad" will just mysteriously disappear from our math.  Some people don't include it at all.  This is because radians is a dimensionless unit.  Why? What does that mean? 

3.  When people don't include radians at all, what units do they use for angular velocity?

3.  One rotation = _____ radians

Today:

  • Return tests and retakes -- retake videos are in Google Classroom.  Anyone who wants to take the Energy, Gravity, Circular motion test can have one more try, but you need to set up a time to do it, outside of class time, before the end of the quarter.
  • Unit 6 Handout #1 -- Rotational Motion and Rubber Band Cars  (PDF)
  • In Block B1/2, spend 30 minutes on "Class Notes Version" of the homework.  Then stop and assemble cars.

Homework:  

Class 14: Thursday, 3/16

Warm Up:  None

Today:

  • Test -- Momentum and Impulse
  • If there's time -- Assemble rubber band practice cars
    • Look at this Parts Diagram
    • Watch this assembly video
    • Some of the actual parts look a little different than those in the video.  Here's how...
      • Colors of 3D printed parts are different -- everything is red, because the library only had red
      • The pin harness and rubber band harnesses look different, because they're 3-D printed.  They actually look like this...
    • If anyone wants some design files (to do your own CAD design and modifications), they're in this folder.

Homework:  

  •  None
Class 13: Thursday, 3/12

Warm Up: 

1.  Solve this simple problem... a 100% efficient 1kg toy car uses its motor to accelerate from rest across level ground.  If the motor uses 0.5J of energy during this process, what is the car's final speed?

 

2.  Does the entire 0.5J of energy get transferred to the car, or does some of it also go to the Earth?  Do we need to recalculate the car's speed to account for the energy that is transferred to the Earth?

 

Today:

Homework:  

  •  Momentum and Impulse test next class
Class 12: Tuesday, 3/10

Warm Up:  None

 

Today:

  • Test retake: circular motion, gravity,

Homework:  

 
Class 11: Friday, 3/6

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 the notes (#16 on p.3)
  • Choose Rubber Band Car Groups -- so that I can gather sufficient materials
  • Questions about the circles and energy test retake?
  • Other stuff?
    • Force plate
      • Bouncing
      • Jumping
      • Dropping
    • Gauss Gun
    • Newton's Cradle -- how it works (partly)
  • Start Momentum and Impulse practice test

Homework:  

  • Test retake next Tuesday
  • P. 7-8 (practice test) due next Thursday Momentum and Impulse Handout (pdf)  Handout Key -- The multiple choice questions are probably trickier than the questions on the real test.
  • Optional:  there are more practice problems in the handout that I don't plan to assign for homework.  Try them if you want more practice.

 
Class 10: Wednesday, 3/4

Warm Up: 

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

2.  The momentum formula is p = mv  (momentum is "p").  Can you explain the balls' behavior in terms of the momentum formula?

3.  How could this concept be applied to towel snapping?

Today:

Homework:  

  •  Problems 1-3, 10, and 13 on p. 4-6.  Handout Key
  • Test retake next Tuesday
    • If you want more roller coaster problem practice, watch this video.  Then print out a fresh copy of page 8 from the last handout.

 
Class 10: Thursday, 2/19

Warm Up: 

There is a "pith ball" hanging next to the Van de Graaff generator.  The pith ball is foam that is covered with a conductive, metallic paint.  What do you think will happen when the Van de Graaff generator builds up a strong negative charge?  Why?

Today:

Homework:  

  •  Have a great break!
Class 9: Tuesday, 2/17

Warm Up: 

Today:

  • Test

Homework:  

  • None
Image result for compound bow drawnClass 8: Friday, 2/13

Warm Up: 

How and why does a compound bow change the nature of W=Fd?

Today:

  • Check/review homework
  • Test review (test on Tuesday)
  • If there's time -- start some static electricity demos

Homework:  

  •  Test prep
Class 7: Wednesday, 2/11

Warm Up:  None

Today:

  • Try out the sled park feature
  • Work time

Homework:  

  •  Continue practice test
Class 6: Monday, 2/9

Warm Up: 

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

2.  If you ride as fast as possible in one gear, how does your acceleration change over time?

3.  How does changing to a higher gear affect the F and d components of your work (e.g. Fd vs Fd)?   Consider changes to F and d where your foot meets the pedal and where the tire meets the road.

4.  At what point should you change gears?

Today:

Homework:  

  •  Practice Test -- due on Friday  Answers
  • Test on Tuesday
Class 5: Thursday, 2/5

Warm Up: 

In this video, a driver supposedly enters a loop-the-loop at a speed of 36mph (16.1m/s).  The driver supposedly experiences 6g at the bottom and approximately 0g at the top.  They say the loop is 40feet high, so the radius is approximately 6.1m. 

1.  In all of the practice problems we have done so far, how many more gs are experienced at the bottom of a loop-the-loop, compared to the top?

2.  Why isn't that the case here?

3.  Does the driver really experience 6g at the bottom, or is it closer to 5g?

*This would be a good context for a bonus problem.

Today:

  • Check/review homework
  • The real sled launch will be next Wednesday.  Tuesday was just data collection, so we can figure out how to do next Wednesday safely.  Bring warm stuff again.
  • Work on the roller coaster problem

Homework:  

  • At least #1 and #2 (and #3 if you want a little more practice) of the Sledding Energy Problems (pdf)  Solutions
  • Optional -- think about how we should design a jump to give everyone a comfortable landing.  We have some control over speed, but not super-precise control.  The current dimensions of the snow pile that we have to work with are (very roughly) about 15m long x 3m wide x 1m high.  I made this spreadsheet to let you easily visualize the flight paths of 3 jumpers.  You can make a copy and adjust the values.  I haven't reviewed all of the video from Tuesday, but our velocities ranged from about 18mph to 35mph.
Class 4: Tuesday, 2/3

Warm Up: 

We're going to use the law of conservation of energy to find out how many pullers it takes to accelerate the sled to a target speed -- for any occupant mass.

 

1) What does this equation look like for the 15m (approximately) over which the sled accelerates?

2) How are we going to use this equation to find the number of pullers required to accelerate the sled to a target velocity?

3) What data do we need to collect?

Today:

  • Check/review homework
  • Sled Accelerator Data Collection -- there's a google spreadsheet in Classroom.
  • Homework work time

Homework:  

  •  P.10-11 (#1-4)
Class 3: Friday, 1/30

Warm Up: 

1.  Why do we have tides?

2.  Why is there a high tide on the opposite side of the Earth from the Moon?

3. Which object is excerting a greater gravitational force on you right now, the Moon or the Sun?

4.  How are tides related to black holes and spaghettification?

 

Today:

Homework:  

Class 2: Wednesday, 1/28

Warm Up: 

We don't have to answer all of these.

1.  What is the net force acting on the jogger in the video?  What is exerting this force?

2.  Approximately how fast is the jogger in this video moving?

3.  If the jogger turned around and jogged the other way, would he feel any different?  What if he ran faster? 

4.  What if the floor didn't have any friction (and no drag in the air)?

5.  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?

6.  There are essentially two ways to simulate 1g of gravity in "outer space."  What are they?  How are they similar?  How are they different?  How do they compare to real gravity?

 

Today:

  • Check/Review Homework
  • Newton's Law of Gravitation -- and practice problems.  Video is on the class playlist.
  • Sled accelorator data collection on Tuesday (Friday is too cold and too soon).  Wear warm clothes and footwear with good traction.  Bring a helmet if you want to wear yours.

Homework:  

  • Four Problems
    • P.6, #16
    • P.7, #3
    • P.8, #4
Class 1: Thursday, 1/22

Warm Up:  What's happening to this guy?  Why? 

Today:

  • Return exams
  • Are there any more completed course recommendation sheets out there?
  • Mid-Year Mop-Up -- tentative plan --  2 classes each of: centripetal motion/gravity, energy/work, momentum/impulse.  Then a practice test and a test.
  • This new unit is interesting, but it doesn't have to be hard.  There are just three new things... 1) Net force = mv2/r   2) Net force is centripetal   3) We have a new way to calculate weight/Fgravity
  • Unit 4 Handout:  Centripetal Acceleration and Gravity (PDF)  Answer Key
  • Derivation of ac = v2/r (direction and magnitude)
  • Work through Handout:  VIDEO of today's notes
    • Change the name of the handout to "Unit 4."
    • Get rid of the last part of the problem on the first problem #4 (p.3)
    • Work on practice problems 1, 2, and 4, on p. 3-4.

Homework:  

  • 3 problems on 2 different pages:
    • Page 3, #3 and #5

Link to 1st Semester