Physics (E1) 2019-2020

With our shift to remote learning, I'll be (valiantly attempting) to orchestrate my courses using Google Classroom. Students, you should have already received an invitation via your Profile e-mail account. The adventure begins!

Friday, March 13, 2020

1.) Quick workshop: A few electric field practice problems.

2.) Graphic representation of electric fields.....

Is there a way for us to to draw or visualize electric fields in a way that is useful?

*Electric field lines........not the same as electric field vectors......but they help you visualize the electric field vectors.

4.) Phet - https://phet.colorado.edu/en/simulation/legacy/charges-and-fields

https://phet.colorado.edu/en/simulation/legacy/electric-hockey

HW: Watch the following videos.

https://www.youtube.com/watch?v=g287MugJC9E

https://www.youtube.com/watch?v=XW0fvr_5Ens

3-D animation explanation of voltage .............. https://www.youtube.com/watch?v=-Rb9guSEeVE

Wednesday, March 11, 2020

1.) Electric fields (and comparing them to gravitational fields)

2.) HW Check--in.

3.) Electric field produced by a point charge? A point charge is an easy-enough distribution of charge that we can actually get a function for the value of the electric field in the region around the point charge.

4. ) Laser Talk: So, share some of the interesting laser applications you found out about. Also, what was, for you, the trickiest aspect of understanding how lasers work?

HW: Nothing new.

Monday, March 9, 2020

1.) So, if light is a wave, WHAT is WAVING?!

2.) Hmmmm....well, until we find out, how about we learn about electric and magnetic fields...

3.) Intro to Electric Fields.

4.) Mini-workshop: Laser Research (Remember to take a serious gander at the rubric I provided.)

HW: 1.) Read p. 425-427 of the "Electric Fields" handout.

2.) Problems #1-4 on p. 427

3.) Coming soon......building an electric motor. Maybe a couple different designs.

4.) Finish up your laser paper and share it with me before you come to class on Wednesday. Be prepared to speak intelligently and productively about it with the rest of us.

Friday, March 6, 2020

1.) Test: NPT and Wave Theory of light; Foucault and Michelson.

2.) Workshop: Laser Research

HW: Laser Paper is due on Wednesday, March 11. Please have it shared with me before class.

Wednesday, March 4, 2020

1.) Laser Research Fest.

HW: Test on Friday. Snell's Law, Particle and Wave Theory Version of Snell's Law, NPT and wave theory derivations of Snell's Law, significance of Foucault's experiment and Albert Michelson's velocity of light data.

Monday, March 2, 2020

1.) So, light is a wave of some sort !!!!! Oh yeah, oh yeah, oh yeah, oh yeah. Wait......if it's a wave, then what, exactly is "waving"? Hmmmm.......

2.) Let's check in with the double-slit interference HW problems.

3.) Lasers. Well, we used them in the last experiment. What, exactly, are lasers? What's so special about them? Are there different kinds? What, besides cat toys, are some cool applications of lasers?

HW: 1.) Quiz coming up: NPT and Wave Theory derivations of Snell's Law. Description and significance of Foucault's experiment. Relevance of Albert Michelson's velocity of light in air to velocity of light in water data.

2.) Make progress on the Laser Research Paper.

Laser Research. This is a chance to learn more about lasers, while also getting good at writing a dense, no garbage, clear, informative paper about a topic. Any more than three pages of 12 pt text and I won't read it (Although diagrams may make your paper take more than 3 pages.) So, you'll have to think carefully about the purpose of each sentence and avoid fluffy, don't-really-accomplish-very-much sentences. This is in contrast to some of my writing experiences in high school, which often felt like it was about filling up pages with words.

Your audience: People with about the same scientific background and training as you.

Topics to address (AND MAKE USE OF THE RUBRIC ! ) :

a.) What is unique about laser light? (Hint: There are 3 main characteristics.)

b.) How does a laser create light? (You know about electron energy levels and photon emission from chemistry. You definitely need to explain the difference between spontaneous emission and stimulated emission, and connect it to population inversion.)

c.) Are there different types of lasers (Lasing material? Continuous wave or pulse? Able

to be tuned or not? Other?)

d.) Then pick two (interesting to you) applications of lasers to describe. Include what

type of laser is used and why. Also, what advantage does using a laser have over

some other method? Probably a solid paragraph for each application, not just a sentence.

Diagrams or pictures? Yes, you can certainly include these. And they don't count toward the limit of 3 pages of text. So, your paper may be 4 pages long, but only include 3 pages of text.

Here are some sites to get you going on the laser stuff...

http://hyperphysics.phy-astr.gsu.edu/hbase/optmod/lascon.html#c1 (LINK REDIRECT)

https://www.norwegiancreations.com/2018/04/laser-101-pt-1-the-basics/

http://www.colorado.edu/physics/2000/lasers/lasers3.html (LINK NO GOOD)

http://www.colorado.edu/physics/PhysicsInitiative/Physics2000/lasers/lasers2.html (LINK NO GOOD)

Winter Carnival and Winter Break !

Wednesday, February 19, 2020

1.) Wavelength of red light? How do the values from the "exact" double-slit interference equation compare to what you get from the approximation equation?

2.) So, find the wavelength of violet light.

3.) Albert Michelson as a character in a Bonanza episode.

https://www.youtube.com/watch?v=vdqjE0jcag4

HW: Finish practice problems #1-4 on p. 395 of the "Diffraction and Interference of Light" handout.

Thursday, February 1, 2018

Monday, February 17, 2020

1.) Can we derive a double-slit interference equation? If we can , this may help us better understand the relationship between the variables involved, and might help us design an experiment to test if LIGHT does this double-slit interference thing.

2.) Laser double-slit interference lab. And what exactly is a diffraction grating?

3.) AND...........WHAT DO WE SEE?!?!?!?!??!?!?!

HW: Use the data from the lab today to calculate the wavlength (?!?!?) of the red laser light!

Friday, February 14, 2020

1.) So, last class we saw that water waves do some of the things we know light does. This is encouraging for our little idea that maybe light is some kind of wave.

2.) HW Check-in: The basics of waves. Longitudinal and transverse waves; mechanical waves are waves that require a medium (like water, or slinkies, or air); frequency, wavelength, amplitude, crests, troughs. Wave pulses vs periodic waves.

3.) Slinky Playing: Interference? Constructive and destructive interference?

4.) Do water waves do anything that we HAVEN'T seen light do? Double-slit interference of water waves on the wave table.

5.) Does light do this "double-slit interference" thing? Our first crude attempt was definitely not convincing.

6.) Hmm....well, what else is a wave that might exhibit double-slit interference? SOUND WAVES?! Sound wave interference demo. THEY DO! THEY DO!

7.) OK, so next time we'll try to be more quantitative about how double-slit interference works (yup, a derivation). Perhaps this will help gives us some clues about how we might observe light do this, assuming it even does.

HW: Nothing new. BUT make sure YOU can derive both the NPT versions of Snell's Law AND the wave theory version of Snell's Law.

Wednesday, February 12, 2020

1.) Well, our particle idea of light got kicked in the buttucks by Foucault's experiment.

So, what else travels and delivers energy? Perhaps light could be some type of whatever this other traveling, energy-delivering thing is?

2.) Wave Table: Do water waves do any of the things that we know light does?

Reflect? Refract?

2.) So, did our wave table observations encourage or discourage our nascent little wave theory of light?

3.) Basics of Waves.....hopefully mostly review.

HW: Read pp. 297-309 of your handy little physics book. As usual, this is mostly questions/problems, which you should really do as you go. Yup, you can easily check your answers which are directly below the question. This "SHOULD" be partially review from back when you were little 9th grade tikes and tikettes.

Monday, February 10, 2020

1.) Snell's Law and the NPT version of Snell's Law reminder.

2.) Hmmm......so can we actually find out if the speed of light in water is greater than the speed of light in air?

3.) Acting out Foucault's experiment. (Keep in mind, Newton developed his particle theory of light in the late 1600s. It wasn't until 1850 that Foucault was able to perform this experiment. Sometimes we need to be patient.)

4.) So, what do the results of Foucault's experiment mean for our budding particle theory of light?!

5.) Well great. What else travels and carries energy?

HW: On your own, make sure you can explain Foucault's experiment regarding the speed of light in air and in water, and how it impacts our confidence in the NPT of light.

Friday, February 7, 2020

***SNOW DAY***

Wednesday, February 5, 2020

1.) Snell's Law review. How did it go?

2.) So, what COULD light be? Wait, what does it do? What could explain that?

3.) So, IF light is weeny, screaming fast particles of some kind, can we derive Snell's Law, or something that appears to be equivalent to it? (Derivation of Newton's Particle Theory version of Snell's Law)

4.) Does the NPT version of Snell's Law PREDICT anything that we could, hopefully, test? And then either support our budding partilce theory of light or, maybe, make us doubt it?

HW: On your own, derive the NPT version of Snell's Law and show we can make a prediction when comparing this result to what we know about refraction for the air-water interface from the angle measurements we took in the lab.

Monday, February 3, 2020

1.) Some on-the-board torque problems. And rotational motion problems check-in (from the video)

2.) Where are we going next? Well, we've worked quite a while (months) learning about how particles move and respond to forces......So now, how about we get back to our question, "What is light?"

3.) So, can we build a model/theory of what light IS?

Well, jeepers, what COULD it be......?

3.) Before we REALLY jump into that, you will all need a refresher about Snell's Law.

HW: 1.) I'm guessing some of you may need a reminder about the basics of Snell's Law...

a.) Light is traveling through air (n = 1) and hits clear plastic (n=1.47) with an incident angle of 62 degrees. Find the refracted angle and draw the picture showing the situation and the angle you found.

b.) Light already traveling inside the plastic from part (a) hits the interface with air at an incident angle of 75 degrees. What is the refracted angle in the air? What happens? Draw the situation.

Friday, January 31, 2020

1.) Workshop: Rotational Motion problems from the HW.

2.) Rotational Motion Problems Problem-Solving Fest with Oommen.

https://www.youtube.com/watch?v=o8LvRDmozaA

HW: Find 4 "interesting/challenging" problems from Dr. Oommen George's video and solve them! Integrity here, folks. Fully try the problems before hitting the play button to see how he solved them. Note the time stamp of the video for your 4 problems so that we can quickly find them in class.

Wednesday, January 29, 2020

1.) Linear (translational) motion vs Rotational Motion comparison (continued)

2.) Clarifying torque. (Bonus: Multiplying vectors two ways: dot products and cross products)

3.) Workshop: Rotational Motion problems

HW: Finish up the Rotational Motion problems handout.

Monday, January 27, 2020

1.) Energy Lab wrap up. Were you able to write the rotational kinetic energy of the all as (some number)*(linear kinetic energy)? So, for a rolling solid ball, the rotational kinetic energy of what percent of the linear kinetic energy?

2.) Rotational Motion is very similar to Linear (Translational) Motion! So, we can use everything you've already used to figure out how to deal with rotational motion quite quickly.

HW: 1.) Clean up anything you need to from your Energy Lab and the Energy Lab spreadsheet. Hand in (or share) with me by next class.

2.) Rotational Motion problems handout.

Friday, January 24, 2020

1.) Results from your "work done by friction" analysis?

2.) What percentage of the original gravitational potential energy (from each of the three release points) is not yet accounted for (after getting value for the kinetic energy and the work done by friction)? WELL, NOW WHAT?!?!

3.) Spinning bike wheels and whether or not to stick your hand in the spokes.

4.) OH, an object can have ROTATIONAL kinetic energy, not just translational kinetic energy (what you've considered so far).

5.) What's the rotational version of velocity? Angular velocity.What's the rotational version of mass (amount of stubbornness about changing velocity)? Moment of inertia (amount of stubbornness about changing angular velocity). Moment of inertia reference sheet. The mass and the distribution of the mass relative to the rotation axis are both important.

HW: 1.) Fix up your Energy spreadsheet as needed.

2.) From the end of class......Write an expression for the rotational kinetic energy of the solid sphere (ball). Use the reference table for the moment of inertia. And use the relationship v=wr to substitute for w (angular velocity) in the rotational kinetic energy equation. Simplify it to something that looks like.........(some number)*(1/2* m*v^2). This way, we'll be able to find the rotational kinetic energy using the translational kinetic energy we've already found ! Lazy! Clever!

Wednesday, January 22, 2020

1.) Back to the Energy Lab, this time determining the rolling friction/air resistance on the ball. We want to find out how much work was done by friction when the balls were rolled down the ramp from the three release points. Will this account for the energy "loss" we've observed?

2.) Set up a spreadsheet to receive this data and perform the needed calculations (This is known as being appropriately lazy.)

3.) Collect the data.

HW: Results?

a.) Find the average work done by friction for each of your three release points. Does the frictional force (and therefore the work done by it) seem to depend upon the velocity?

b.) Make another little table in your spreadsheet that includes columns for the original potential energy for each release point, the (average) kinetic energy at the bottom of the ramp for each release point, and the average work done by friction for each release point. Do the sums of the kinetic energy and work done by friction equal the original potential energy?

MLK Day

Friday, January 17, 2020

1.) Energy Lab....continued.

2.) So, now that you've taken the data and performed the calculations, how does the kinetic energy at the bottom of the ramp compare to the potential energy at the release point of the ball?

3.) OK, now what?!

4.) Energy Lab: Determining the total rolling friction of the ball

* Build a spreadsheet for yourself that allows you to input whatever raw data that is needed from your 4-photogate experimental set-up. Then have the spreadsheet be able to automatically calculated the total rolling friction for multiple trials.

5.) Run your trials.

HW: Good job, today.

1.) Now, find the average total rolling friction acting on your ball based upon your (4?) trials.

* How consistent were the forces you found, trial-to-trial?

2.) Using your three different rolling distances from the original ramp set-up, find the number of Joules of energy accounted for by the frictional work. I wonder how well this will make up for the discrepancy we saw between the potential energy at the release point and kinetic energy at the bottom of the ramp.

Wednesday, January 15, 2020

1.) Return your quizzes. Not nearly as horrible as you all were worried about.

2.) Energy Lab*How the photogates work, including daisy-chaining them.*Building the ramps and starting to take velocity data.

HW: If you have the data, finish the calculations for the big chart on the 3rd page. IF you can slip in during flex block to finish taking the data, go for it. Otherwise, save it for Friday.

Monday, January 13, 2020

I'm out with the plague.

1.) Option #1: IF you need finish up or catch up on any of our recent work, you may do so.

Option #2: Watch this geeky awesome video about the elements, but with the twist of actually seeing how we get them.

https://www.pbs.org/video/nova-hunting-the-elements/

HW: Catch up on anything from the course that you need to.

Friday, January 10, 2020

1.) Quiz. Topics: Momentum, Impulse, Conservation of Momentum, Kinetic Energy, Work-Change in Kinetic Energy, Circular Motion

HW: Get better. Several of you seem to have the plague.

Wednesday, January 8, 2020

1.) Stories about jury duty, if you're interested.

2.) Workshop: Preparing for the quiz.

HW: Quiz next class. Topics: Momentum, Impulse, Conservation of Momentum, Kinetic Energy, Work-Change in Kinetic Energy, Circular Motion

Monday, January 6, 2020

1.) Welcome back!

2.) Intro. to the Energy Lab. What are we hoping to accomplish? Confusion and revelation, folks, confusion and revelation.

*Basic set-up.

*How the daisy-chained photogates work.

*Developing a testable hypothesis regarding the initial potential energy of the ball on the ramp and it's kinetic energy as it leaves the ramp at the bottom.

*Gathering data.

HW: Some review of recent handiness we've been enjoying.

"Impulse and Change in Momentum" handout.

#2-4 on p.179.

#6-8 on p.185.

#9 on p.188.

#12 on p. 189

#15 on p. 191.

Holiday Vacation

Friday, December 20, 2019

1.) Assorted Santa and reindeer physics, puzzles, and annoyingly awesome problems.

HW: Enjoy your holiday break! Go play outside. Read a good book. Take a nap. Play outside some more.

Wednesday, December 18, 2019

1.) "Forward Accident Analysis" results? So, now long a skid mark do you expect given the velocities and masses of the vehicles involved, and the amount of friction?

2.) OK, NH Accident Analysis Group. There's been a terrible accident involving two vehicles and a green, clay snowman. Gather data from the accident scene and determine if either vehicle was speeding right before the collision.

HW: Clean up your problem-solving from today. The main point is to make sure YOU feel confident moving through the problem on your own.

Monday, December 16, 2019

1.) Two "extreme" types of collisions. Most collisions aren't quite either of these extremes, but some are pretty darn close. You may appreciate this hyperphysics resource. http://hyperphysics.phy-astr.gsu.edu/hbase/colcon.html#c1

a.) Elastic collisions. (Energy is conserved. Momentum is conserved. Kinetic energy is conserved.) Reasonable real-life example?

b.) Inelastic collisions. (Energy is conserved. Momentum is conserved. Kinetic energy is NOT conserved.) Reasonable real life example?

2.) Car and Tesla Truck collision problem?

HW: Finish the (forward direction) accident analysis problem. What is the length and direction of the resulting skid mark(s)? Again, you're assuming the logging truck and hummer stick together when they collide, then skid to a stop.

Wednesday, December 11, 2019

Early-release day. Classes a bit shorter.

1.) Review of impulse and momentum, and how it's connected to what we already know.

2.) Workshop: Some impulse/momentum problems.

3.) Collisions: connecting impulse, change in momentum, Newton's 3rd Law...............to get.......Conservation of Momentum?

HW: Nothing new.

Monday, December 9, 2019

1.) Good job on your tests!

2.) The stopping Santa's sleigh problem.

(Total) Work = Change in Kinetic Energy

3.) Momentum and Impulse.

HW: Your handy little Physics books. Read pp. 87-1st half of 94. Do lots of the little exercises along the way. They are not very challenging, but are kind intros to momentum and impulse.

Friday, December 6, 2019

1.) Test: 1-D and 2-D motion, friction, circular motion

HW: The Santa's sleigh stopping on the roof problem (see the HW from Wednesday).

Wednesday, December 4, 2019

1.) Work? Kinetic energy? Remember those happy ideas?

Connection?!

2.) Workshop: Prepping for the test on Friday.

HW: 1.) Work-KE problem.

The skidding to a stop problem, revisited. So use the Work-KE relationship to help you do this problem a bit more elegantly than our previous approach.

a.) You are testing Santa's sleigh. You load it up so that the mass is 2000kg and then tell the reindeer to land on a flat, snowy roof where the kinetic coefficient of friction with the sleigh's skids is 0.3. Rudolph brings the sleigh in hot and touches the roof at 10 m/s. How much distance is required to stop the sleigh? (Assume it slides to a stop.)

b.) Given the size of most residential roofs, will Santa need "special elf dust" to accomplish this landing? (Answer choices: a) No, not needed, b.) Rudolph needs to go into "elf dust" rehab, c.) Heck yes. d.) Santa should definitely be banned from the Olympics for systematic use of performance-enhancing "elf dust". )

2.) Test on Friday! Topics: 1-D and 2-D motion problems (like soccer balls being kicked off cliffs and woodchucks sliding to a stop); vectors (components, adding by any of the 3 methods we worked on); circular motion; friction (kinetic and static); gravity; combining these ideas together.

Monday, December 2, 2019

1.) Heads Up! Test on Friday. Topics: 1-D and 2-D motion problems (like soccer balls being kicked off cliffs and woodchucks sliding to a stop); vectors (components, adding by any of the 3 methods we worked on); circular motion; friction (kinetic and static); gravity; combining these ideas together.

2.) Workshop

HW: Use problems we created together in class today to prep for Friday's test. We'll workshop some on Wednesday, but also introduce some new material, too (that won't be on Friday's test).

Wednesday, November 27, 2019

1.) Radius for the orbit of the moon around Earth?

2.) Lots of orbit-related questions from you guys.

HW: Enjoy your Thanksgiving!

Monday, November 25, 2019

1.) Geostationary orbit calculation?!?!?!?

2.) How does this radius compare to the radius of the Earth? Is geostationary "near" Earth or is it multiple Earth radii away?

HW: OK, so the moon takes about 28 days to orbit the Earth. Use your swanky physics skills to find out how far from Earth it is.

Friday, November 22, 2019

1.) Centripetal force check-in? Did you discover that you need to square the velocity in order to make the units work out correctly?

2.) Using centripetal force to help understand driving around curves. What force actually PROVIDES the centripetal force? FRICTION !

Yay, we get to practice friction AND centripetal force at the same time. And learn about driving around curves in the summer vs the winter.

3.) Back to satellites. So, what actual force is available to provide the needed centripetal force for satellites orbiting Earth?

4.) Hmmm.....so is there a relationship between the distance the satellite is from Earth (r) and the velocity for that orbit?

HW: a.) Find the radius (distance from the center of the Earth) for a geostationary orbit. In class, we realized this meant the time for the orbit had to be 24 hours (? seconds), while the satellite moved the circumference of a circle (2*Pi*r). So, that gives a relationship between the v and the r. We also figured out the relationship between v and r for ANY orbit (not worrying about the specific time one orbit took). So, make BOTH conditions be true at the same time. Yay, solving a system of equations.

b.) So you found r, the distance from the center of the Earth, for the geostationary orbit. How far above the surface of the Earth is this?

All assignments are due at the beginning of the next class unless a different due date is noted.

Wednesday, November 20, 2019

1.) Pushing the crate problem.

2.) Circular motion. Is an object moving in a circular path accelerating? If so, in what direction? And does that mean there has to be a force in that direction? How much does it need to be?

HW: OK, you quite reasonably reasoned that the centripetal force was proportional to the mass and velocity of the object, and inversely proportional to the radius of the circular path. Knowing what you know about units, check your hopeful little equation to see if the units work out. Suggest changes if you think you need to.

Monday, November 18, 2019

1.) Starlink findings? Space law? Internet?

HW: There is a crate of Starlink satellites on the ground in front of you. Assume the mass of the crate is 40kg, the kinetic coefficient of friction between the crate and floor is 0.53, the static coefficient of friction between the crate and floor is 0.78, and you have your favorite socks on.

a.) You push (continuously) horizontally on the crate with 300 N of force. Where will the crate be 3 seconds after you start pushing?

b.) You push (continuously) horizontally on the crate with 310 N of force. Where will the crate be 3 seconds after you start pushing?

Friday, November 15, 2019

1.) Motorcycle Stunt Simulation results?!? Which ramp? What speed? Any disagreement?

2.) Frozen Woodchucks of Death problems. How did they go?

3.) v(t) and x(t) derivation quiz

4.) What is Starlink? Go find out a bit about it, then we'll get back together and come up with more questions about it.

How many satellites (operating or not) are already orbiting Earth?

How many satellites are planned for the Starlink "constellation"?

Are they visible? Will they be visible when operating? Is anything being done to make them less visible?

Do you need permission to put satellites up? From whom?

Is there "Space Law"? Is space law and conflict resolution capable of handling current, um, technological capabilities?

Where will they be? How far apart will they be from each other? How high?

What's a geostationary orbit? Will these satellites be in these orbits?

Any concerns about these satellites?

Are there other companies/organizations that are also developing these systems or are seeking approval?

What is "latency" with regard to an internet connection?

Is latency a concern in any way with satellite-based internet?

HW: Pick about 3 of the questions we generated about Starlink and go find out what you can about each one. If you stumble upon a question that is more interesting (to you) than one we came up with, go find out about that one.

Wednesday, November 13, 2019

1.) Workshop: Can you derive v(t) and x(t)? Huh, can you?

2.) Friction: A basic model for the frictional force.

3.) Frozen Woodchuck of Death.

4.) Workshop: Motorcycle Stunt Simulation

HW: 1.) Finish/refine your Motorcycle Stunt Simulation. Read the directions for it! CLEARLY present your findings to the insurance company. Make sure you explain WHY you ended up choosing the ramp and velocity you did. Discussion of what factors affected your choice would be reasonable.

2.) Finish up the Frozen Woodchucks of Death problems.

3.) Derivation of v(t) and x(t) equations could happen any class now!

Friday, November 8, 2019

1.) Motorcycle Stunt Simulation.

Want help drawing the window?

A convenient way to input the x(t) and y(t) sochanging velocities is quite easy.

HW: Make huge progress on the Motorcycle Stunt Simulation. Pay attention to the insurance company's reporting requirements!

Wednesday, November 6, 2019

1.) Slow it down and check in on the Emma-on-the-roof problems.

2.) Using the parametric equation features on the graphing calculator. And then graphically showing the simulation for a trajectory. (Also, adjusting the min and max times, and adjusting the x and y mins and maxes.)

3.) Motorcycle Stunt Simulation. (And, as required, the Pickle Song by Arlo Guthrie.)

HW: Make progress on the Motorcycle Stunt Simulation. (Which ramp would you and your stunt crew use to make the jump? Why?)

Monday, November 4, 2019

1.) 2-dimensional motion. (The Emma kicking something off her roof scenario.) Let's catch folks up who weren't here last class, and add a twist or two to the scenario for the folks who were.

HW: Refine/retry/finish the problem scenario from class.

Friday, November 1, 2019

1.) Miro, Chris, and Emma strong-arm me into showing them how any number equals any other number. Your 60 on your test? No different than a 100!

2.) Spud physics. Which hits first, the dropped potato or the horizontally shot potato? And let's see what actually happens using the metal ball shooter/dropper doo-hicky.

3.) Using the position equation for two-dimensional problems.x(t) and y(t) and..... z(t) if you need to deal with 3-D.

4.) Emma rages out and kicks the metal ball shooter/dropper doo-hicky (which was ill-advisedly given to her as a Christmas gift) off the roof of her house on Christmas morning. Her house roof is 15 meters off the ground. She kicks the gift with an initial velocity of 25 m/s at an angle of 38 degrees above the horizontal.

a.) Write the the x and y position equations and x and y velocity equations the flight of the gift.

b.) How far from the house does it land?

c.) What's the highest above the ground the gift gets?

d.) Find the total impact velocity as it plows into the ground.

Wednesday, October 30, 2019

1.) Test: Vectors, Newton's Laws, Weight and Gravity.

2.) Using the position and velocity equations for two-dimensional problems. Dropping a potato vs shooting a potato (horizontally)

HW: Solve for the time it takes each potato (dropped vs shot horizontally at 60 m/s) to reach the ground when released/shot from 1.5 meters off the ground. So, which potato hits the ground first?

Monday, October 28, 2019

1.) Heads Up: Test next class. The new v(t) and x(t) modeling is NOT on this test. Topics: Vectors, basics of Newton's Laws, weight/force of gravity.

2.) Test prep workshop.

HW: Prepare for the test. You might give yourself two vectors and add them using the three techniques we've worked on. Also, can make the F, v, a situations like we did in class and decide if they're possible or not.

Friday, October 25, 2019

1.) Position equation: Let's use that puppy.

2.) Force of gravity....reminder? Where does "little g" come from?

3.) Test prep problems.

HW: Test coming up Wednesday!

Wednesday, October 23, 2019

1.) Position equation derivation. The fun and the glory.

2.) Test coming up next Wednesday.

HW: Practice the v(t) and x(t) derivations. Also, test coming up on Wednesday. Topics: Vectors, Newton's Laws, Weight and gravitational force.

Monday, October 21, 2019

1.) Basic Newton's Laws problems check-in.

2.) Developing motion equations: Deriving v(t) and x(t) equations (Velocity and position equations). *This lets us develop mathematical models for how an object will move.

HW: Most likely finishing up some graphing and some questions from the v(t) and x(t) derivation handout. Let's see where we get.

Friday, October 18, 2019

1.) Modified plan for the 2nd relief flight from Santo Domingo to San Juan? How long will it really take?

2.) Review: Basics of Newton's Laws.

HW: 1.) Enjoy the little velocity, acceleration, and Newton's Laws exercises from the handout.

Wednesday, October 16, 2019

1.) Relief Flight #1. What's your airspeed? (velocity relative to the air)

2.) You did such a good job with the first relief run, you are asked to manage another the next week. So, same setup and same pilot. This time, however, the wind is blowing toward 20 degrees south of west at 92 km/hr.

a.) So, what do you tell the pilot now for his "airspeed"?

b.) If you have any concerns about your result, make a suggestion to the relief organization regarding scheduling. Be very specific.

HW: Finish up our the second relief flight scenario. Figure out how to deal with the limitation of the planes cruising speed. So, find the air speed (direction), and find the new flight time. The relief organization appreciates your skill and effort. They do, really.

Wednesday, October 9, 2019

1.) Workshop: Vector problems

2.) Vector Addition: Using the Law of Cosines to add vectors; advantage and disadvantage.

3.) Boats and planes and vectors....

HW: 1.) You are responsible for getting emergency supplies to San Juan, Puerto Rico from a fairly damaged, but usable airstrip in Santo Domingo, Dominican Republic. You have a few minutes to finalize your flight arrangements with the frazzled, but capable pilot. However, you know your flight time to San Juan must be 1 hr and 15 minutes to coordinate effectively with relief efforts on the ground there.

Some further info.

* The plane is a Cirrus SR22.

* San Juan is due east of Santo Domingo (pretty close to true)

* The wind is blowing toward 35 degrees north of east at 50 km/hr.

Your frazzled pilot doesn't have access to his usual flight planning info due to the hurricanes and doesn't know what his airspeed (velocity of the plane relative to the air) should be ! ! ! HELP HIM so you can get off the ground and make the flight in time.

Some questions you might want to consider....

a.) How far is it from Santo Domingo to San Juan? Hmm...what units is that?

b.) What is the cruising speed of a Cirrus Sr22?

So, find what the "airspeed" of the plane should be so you can tell the pilot

2.) [Just do #1 for now!] You did such a good job with the first relief run, you are asked to manage another the next week. So, same setup and same pilot. This time, however, the wind is blowing toward 20 degrees south of west at 92 km/hr. So, what do you tell the pilot now for his "airspeed"?

Monday, October 7, 2019

1.) Vector Addition. (Graphically, by components, and using Law of Cosines)

2.) Workshop: Vectors

HW: Give the HW due today another try. Refine or retry problems as necessary.

Friday, October 4, 2019

1.) Questions from the Newton's Laws review problems?

2.) Quick velocity and acceleration problems.

3.) Vector Addition

*Graphically

*By components

*Law of Cosines

4.) Vector Lab. Navigate to http://phet.colorado.edu/en/simulation/vector-addition and run it or download it. Either is fine.

HW: Vector handout.

1.) Read pp.109-119.

2.) Vector problems.

Practice Problems #2-4 on p.112.

Practice Problems #11,12 on p.118.

Practice Problem #16 on p.120.

Wednesday, October 2, 2019

1.) Test: Behavior of Light Topics: reflection and refraction drawings, Snell's Law problems, critical angle, total internal reflection, maybe some questions about applications.

2.) So...what might light actually be? Perhaps, weeny, very fast little particles? Does this idea at least pass the "is this even reasonable?" test? Could little particles do what we've seen light do?

3.) Thus we begin a huge detour. Let's go learn about motion and forces, then we'll return to building a theory of light.

HW: Newton's 2nd Law handout. Give these problems a try. In theory, they are review (from Physical Science back in 9th grade). I know, I know, I know. Use your skills, pay attention to units. Let's see how much falls into place.

Monday, September 30, 2019

1.) Any rainbow questions? Share your spreadsheets with me.

2.) Fiber optics installation. Don't bend them too much!

3.) Workshop: Prepare for the Behavior of Light Test

4.) Intro. to scalar and vector quantitites. https://www.physicsclassroom.com/class/1DKin/Lesson-1/Distance-and-Displacement

HW:

1.) Test on Wednesday. Topics: reflection and refraction drawings, Snell's Law problems, critical angle, total internal reflection, maybe some questions about applications.

2.) Check out the "Distance and Displacement" link (above )if you haven't done so already. Check your understanding by answering the questions. They are quite mellow.

3.) Do the One-Dimensional Motion, Part 1 problem set.

Friday, September 26, 2019

1.) Rainbow Wrap-Up.

Interpreting the Return Angle vs Impact Angle graphs you created.

2.) Secondary rainbow characteristics? So, what light path could be returning light to your eye for this?

3.) Secondary rainbow return angle equation? Add this to your spreadsheet for red and violet light, then add both of these to your Return Angle vs Impact Angle graph.

4.) Ahhhh......so that's what Alexander's Dark Band is and why it happens.

HW: Great work today. Good thinking while also dealing with the technical aspects of the spreadsheet. Test coming up on Wednesday. Topics: reflection and refraction drawings, Snell's Law problems, critical angle, total internal reflection, maybe some questions about applications... Work on what you need to work on......

Wednesday, September 24, 2019

1.) Finish ray tracing for the red light and violet light through the raindrop for your impact angle. Goal: to get the "return angle". We'll share the data and see what we notice before making a spreadsheet do all the gruntwork.

2.) Workshop: Finalize your spreadsheet. I imagine it's the last two columns (calculating the return angles) that may be the most challenging.

3.) Graphing our results. Return Angle vs Impact Angle. What does this tell us?

HW: 1.) Heads Up! Test coming up soon, likely on Monday, maybe Wednesday. Topics: reflection and refraction drawings, Snell's Law problems, critical angle, total internal reflection, maybe some questions about applications... Work on what you need to work on......

2.) What's a secondary rainbow? Check out the photo below. How is it different than a primary rainbow? How is it being created?

3.) Bonus, you are awesome, smarty-pants, question...

What is Alexander's Dark Band, and why does this happen?!?

Monday, September 22, 2019

1.) Rainbow Physics. Heads up about the spreadsheet you will create so that you can calculate the return angle for any impact angle on the upper part of the raindrop. Then, you'll be able to graph "Return Angle vs Impact Angle" and we'll see what this means in terms of how/why we can see rainbows.

2.) Finish your ray tracing: 1.) For RED light with n = 1.331 and 2.) for VIOLET light with n = 1.344.

3.) Comparing data from our ray tracing.

4.) Workshop: Rainbow spreadsheet.

HW:

Make a google sheet. First column is the impact angle (degrees). Second column is impact angle converted to radians. Third column is the refraction angle (for that specific impact angle) for red light. Fourth column is the refraction angle (for that specific impact angle) for violet light. Fifth and sixth columns are the refraction angles (for red and violet, respectively) converted to degrees. Then the big cake-a-doodle......seventh and eighth columns are the Return Angles for red and violet light, respectively. Yes, you'll need to work out how to tell the spreadsheet to calculate this. Remember the big hint from class: Add up the three "turns", then the return angle will be 180-(the three turns added up).

Friday, September 20, 2019

1.) HW Check-in.

2.) http://www.youtube.com/watch?v=OQSNhk5ICTI&list=TL1AeTpgtfWeD5muEP51HMn05pNOAURYpp

3.) Rainbows? Rainbows! Double Rainbows?! How? What do they MEAN ?!?

4.) Lab: Rainbow Physics.

a.) Draw the raindrop and find the center. Have you ever used a mira? No, not a mirror, but it sort of is, though. Crazy simple.

b.) Finding the "return angle" for red light and violet light hitting the raindrop at specific "impact angles".

c.) Noticing our results. Then, setting up a spreadsheet to do some of the heavy lifting for us.

d.) Graphing "Return Angle" vs. "Impact Angle", then wondering what it is telling us....

HW: Rainbow Spreadsheet

Wednesday, September 18, 2019

1.) HW Check-in.

2.) Critical Angle TIR (Total Internal Reflection)

3.) Some TIR (Total Internal Reflection) applications:

a.) Binoculars/telescopes with prisms instead of mirrors

b.) Diamonds! How they are cut matters.

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwi8gdHywa3WAhXk6YMKHR-lCXwQjRwIBw&url=https%3A%2F%2Fwww.quora.com%2FWhich-is-more-important-when-buying-a-diamond-cut-or-clarity&psig=AFQjCNEPYyDfXt19BCeQTH8I1xxA6jwOcA&ust=1505779620501849

c.) Fiber optics for data transfer

d.) Fiberoptic Endoscopy

https://www.youtube.com/watch?v=P2pLJfWUjc8

https://www.fauquierent.net/endo.htm

HW:

1.) If you know you need some more practice with Snell's Law problems, critical angle, TIR and such, prioritize getting that straightened out. Here's a source for some practice problems.

http://www.physicsclassroom.com/class/refrn/Lesson-3/The-Critical-Angle

2.) a.) Draw a picture that shows the critical angle for a water/glass interface. I know you don't know the value of the critical angle yet, but draw it in and label it generically as the critical angle.

b.) Find the value of the critical angle for the water/glass interface (n=1.33 for water and n=1.5 for this glass).

c.) What happens if light is shone from the water to the glass with an incident angle of 70 degrees?

d.) What happens if light is shone from the glass to the water with an incident angle of 70 degrees?

Monday, September 16, 2019

1.) Finish up our analysis of the Refraction Lab data.

2.) Snell's Law. And a link to some indices of refraction. https://www.physlink.com/reference/indicesofrefraction.cfm

3.) Example Problems.

4.) Critical Angle demo. And....finding the critical angle for the interface between two transparent materials. Which material is the critical angle always "in"?

HW: Snell's Law problems.

1.) a.) Light shone from glass (n=1.5) into a sugar solution has an incident angle of 32 degrees and a refracted angle of 36 degrees. Find the index of refraction of the sugar solution.

b.) Find the sugar concentration of the solution in (a). You'll probably find it as a % by weight. Yup, you need to poke around and search for this info, interwebby insta-snapface children.

2.) a.) Draw a picture that shows the critical angle for a water/glass interface. I know you don't know the value of the critical angle yet, but draw it in and label it generically as the critical angle.

b.) Find the value of the critical angle for the water/glass interface (n=1.33 for water and n=1.5 for this glass).

c.) What happens if light is shone from the water to the glass with an incident angle of 70 degrees?

d.) What happens if light is shone from the glass to the water with an incident angle of 70 degrees?

Friday, September 13, 2019

1.) Lab: Refraction (Discovering Snell's Law?) Take your time with the set-up so you can measure the incident and refraction angles as accurately as you can. Use the stands to stabilized the lasers.

2.) Spreadsheet workshop: Analyzing your Refraction Lab data. Can we find some quantitative relationship between the incident angles and the refraction angles?

HW: An applied Snell's Law problem (if we're able to get to the final version of Snell's Law during class today).

1.) a.) Light shone from glass (n=1.5) into a sugar solution has an incident angle of 32 degrees and a refracted angle of 36 degrees. Find the index of refraction of the sugar solution.

b.) Find the sugar concentration of the solution in (a). You'll probably find it as a % by weight. Yup, you need to poke around and search for this info, web children .

Wednesday, September 11, 2019

1.) Quiz: Math Review.

2.) Quiz: Circuit-building practical (I'll call you away from your oh-so-fun math review quiz to come over to the lab to build the two circuits.)

3.) Depending upon how much time we have...... Begin the Refraction Lab and/or check-in on the HW problems.

HW: Re-try, if necessary, the four problems I gave you last time. Remember, such relationships are likely to pop up as we proceed with the Refraction Lab.

Monday, September 9, 2019

1.) Reminder about the quizzes on Wednesday.

*Math Review Quiz. * Circuits Practical Quiz (just with the lab equipment, not the actual house equipment)

2.) So, if we want to develop a theory of what light IS, we should probably pay attention to what light DOES first....

*Some properties of light.

3.) Intro. to the Refraction Lab

HW: 1.) Be totally prepared for the quizzes. You are welcome to stop by and practice building the circuits if you want.

2.) See the handout. Four problems that just might turn out to be handy as we proceed with the Refraction Lab next time.

Friday, September 6, 2019

1.) Math Review check-in??

2.) Wiring challenges. Single-switch circuit on a stud wall. Two-switch circuit with lab equipment. Two-switch circuit on a stud wall?!

HW: Math Review Quiz and Circuits Practical Quiz coming up on Tuesday. You know what to expect.

Wednesday, September 4, 2019

1.) Last group workshop on the mathy review stuff. (And Crosby gets all amped up about the quadratic formula.)

2.) Circuit challenges.

HW: 1.) Quiz coming up soon (not Friday). Topics: Math review type problems.

2.) Start sketching and figuring out how to use two single-pole-double-throw (SPDT) switches, alligator leads, and a battery to control a light.

3.) Coming up: Building a circuit on a stud wall with actual-like-used-in-your-house wiring materials.

Long Labor Day Weekend

Go to a fair. Eat some fried dough and too much cotton candy. Puke on a ride. Call it a Physics experiment.

Wednesday, August 28, 2019

1.) Everyone take a look at the new homework assigned today (below) so that you have it in mind as you workshop the Math Review.

2.) Math Review Workshop Up at the Board

The point is for EVERYONE to have a chance to see what they are or are not doing correctly, and have the opportunity to make revisions to his or her work.

3.) Lab: Wiring Challenges

a.) Do Wiring Challenge #1 . This is a basic circuit with a power supply and bulb that is controlled by one switch (SPST, single pole-single throw).

b.) Do Wiring Challenge #2. This is quite a bit more tricky. This time, there are TWO switches (SPDT, single pole-double throw) that control the bulb circuit. The bulb should be able to be turned on or off from either switch. Many houses have a circuit like this for lights on the stairs, with one switch at the bottom and one at the top. ****CAREFUL***: Check to see if any of the wires are getting quite warm even if the the bulb is off. If this is the case, you are shorting out the power supply and it's not a good solution. You want a solution that does not draw power when the bulb is off.

HW: Math Review Personal Follow-up. Pick 5 of the Math Review problems that gave you the most trouble or that you feel the most uncertain about. Make 5 problems similar to these (So, one of each of your "problem problems".). Solve them, showing your steps clearly. Your goal is to be able solve them confidently on your own at this point. Both the original Math Review Problems AND your 5 "personal" problems will be handed in next time. Whole point: Get confident with the skills that were causing the most trouble for you.

Monday, August 26, 2019

1.) Making a shortcut to the course web site. To get to it the first time, you could just search "Crosby Profile Science". It will be the first hit. Navigate to your section, then bookmark that page, or make a shortcut on your desktop.

2.) Very quick course overview. Competencies. The "What is light?" framework for the course.

3.) Lab: Strange Light Observation - Polarization

4.) Math Review Assignment. What and why.

5.) Might not start until next time......... Lab: Begin the Wiring Challenges.

HW: 1.) Make sure you have less-than-10-second-access to the course web site. That is, once your computer is on, just be able to do a click or two and be able to get our site up.

2.) ON A SEPARATE SHEET OF PAPER, NOT ON THE MATH REVIEW HANDOUT (so you have plenty of room, including re-trying problems), finish the Math Review for Physics. Show your work clearly (except for the calculator ones).