Error!

 

Attention: my final run-through of the numbers on the Compound Pendulum were compared to a grading spreadsheet that has an error in it! (Honest math mistake by me!) So if I told you that you didn't match the key, that statement needs to be challenged. It is possible that you still matched the key. Now I've already fixed this in the gradebook, by adding points back to anybody who got dinged a little for the mismatch, so nobody is being cheated out of any credit points, but if you see this message and are interested in knowing the accurate physics, you may come to my room if you'd like to assure that your final answer on your lab report was done correctly by you. To reiterate: the only reason to come and check this out would be for the conceptual satisfaction. The grade has already been taken care of. All students who did the assignment have had their score corrected so that it's now as if their answer matched the key. (I've given the benefit of the doubt to each student, because all the lab write-ups were nicely solved on paper with clarity. And it had been only a very minor deduction anyway for an answer that didn't match the key. All those points were added back in. And I boosted the assignment to be worth 20 instead of 15!)

 

And most importantly, Alana and Carly still won the contest.

Cutoff scores on the May 1 final:

 

Assuming the test has 50 points (40 MC and 10 points of showing work on rotation),

 

The lowest score to earn a 5 is 39.

The lowest score to earn a 4 is 30.

The lowest score to a 3 is 23.

 

Extra points for putting names on documents, etc, do not add into the raw score in determining 3, 4, 5 scores. From the raw test score alone, a final exam score of 4 or higher makes a student eligible for a letter grade bump. (Completion of all other assignments and not lying, cheating, or stealing are required as well to be eligible.)

 

The lowest 5 goes into the gradebook the way a test 90% would. The lowest 4 goes into the gradebook the way a test 80% would. And the lowest 3 would correspond to a 70% score. Points for following directions, etc. will be added to these gradebook scores only after the 3's, 4's, and 5's have already been determined.

The final is Wednesday, May 1.

 

Final Exam/AP Exam Study Tools:

 

The pdf is a big practice test from the college board. The multiple choice has 50 questions.

I'll post another multiple choice soon.

The topic list was written by me.

Another set of random problems was compiled by me.

 

Instructions for Free Response Practicing:

 

1. Go to this site:

 

2. Pick a year. Open the file. Do the full test by yourself, undistracted, IN TEST-LIKE CONDITIONS. Set a time-limit. Write the solutions out as if a stranger were going to grade them for quality work-showing.

 

3. Sometime soon after taking the test, open the Scoring Guidelines. Use the rubric to score how you did.

 

4. Do two such years BEFORE the end of the week that ends on 4/26. And do at least one of the multiple choice mock tests I provide. From this, make a list of topics you want me to refresh.

 

It's crucial that you don't wait to get to this stuff until the week of April 28th. Do meaningful things from the above list before Thursday of the week before that.

This isn't due to be graded. It's due to be caught up. In class, I said see how you do on the first two pages of it without using the rest.

 

Use the rest (the later pages) to check your answers.

Due March 26:

 

This attached thing. Requires internet simulation. Open it early, and if the simulator doesn't work at home, make plans to do it on an on-campus computer. For most people, it works at home.

Link to those PhET simulations on wave interference:

 

Hi Level Practice Test for Waves - Multiple Choice, with answers at the end - attached

 

About the 2018 Sample Free Response questions: Here is my assessment:

1) I never saw the problem before in my life until 5 PM on 3/14/19, about 5.5 hours after you did it.

2) The main idea in all the arrow indicators asked for was to see how strongly you stick to your guns on the following idea: The mechanical wave transports NO MATTER in the direction of energy propagation. The direction of energy propagation is in the direction of wave velocity. Waves transport energy but not matter.

3) How tempted were you to make the vector responses of part a complicated by not sticking to your guns about the concept I just highlighted in 2 above.

4) As usual, the AP test demands simple responses that are specific and tied to fundamental principles that you have heard stated or seen written. But how strongly do you adhere to them in order to answer exactly what's asked and not take a long time doing it.

5) I haven't looked at the Scoring Guidelines rubric yet. When I do, I expect the answer to show for part (a) that particle Q at the instant shown is to have ONLY a purely vertical velocity vector. I believe this strongly, because I believe strongly that the matter particles of the rope (the medium) cannot be transported horizontally. (And I believe that P's velocity is zero.

6) Because I know the definitions in basic kinematics and Newton's Laws, I believe that P's acceleration at the instant shown is maximum upward while P is instantaneously at rest. I apply what I know about elastically driven motion. I see points P and Q as having a vertical behavior as identical to what I would see for a mass on the end of a Hooke's Law spring. I say that Q has maximum vertical velcocity only and therefore an instantaneous acceleration of zero at the instant shown. And I find a way to check my logic. Zero acceleration corresponding to zero displacement at the instant completely what matches what one would say from Hooke's Law: F = -kx so Ma = -kx which leads to a = -(k/M)x. x is instantaneously zero, so a is as well. (It's not a literal spring. It's like a spring.)

7) When I do part (c), I see how simple it is by sticking to my guns. By knowing that P only has vertical motion, I see how easy it is to answer 32 cm just be being observant and being precise with my definitions. I might even be tempted to say, "Why are they putting something this easy on an AP test." Well, a lot of people write irrelevant nonsense, because their studying doesn't involve reading and prioritizing physical facts. Many people miss these easy questions because of that. Maybe I missed some. I still haven't checked the key.

 

The Scoring Guideline is at the link below, along with all the rest for several years:

 

 

There will be a short quiz Monday to make sure people are practicing and reading. The big full Wave test (Chapters 13 and 14) is Friday, March 22.

Due upon arrival Monday March 4:

Fill in this document as instructed. You will fill in for any chart that was measured in the class on 2/28/19 whether you were personally involved in the measuring or not.

 

That also goes for people who were absent on 2/28/19. Complete this as instructed whether you were in class on 2/28/19 or not.

This

Study Guide Material for Equilibrium in Chapter 8

 

Short Quiz on Wednesday 2/4

Instructions to calculate the score on the semester 1 final.

 

Double the score earned on Free Response number 2* (which had a maximum of 6). Add that doubled amount to the score earned on Free Response number 1. The highest the total free response section score could be is 24. (Doubling number 2 makes each part 12 points*.)

 

Add the free response score to the multiple choice score. Call the final total N. The highest N could be is 73, because there were 49 multiple choice questions.

 

The overall exam percentage is calculated via (N + 17)/90. Whatever this percentage is of 40 is the gradebook score.

 

*Free Response number 2 absolutely needs to be equal weight to the first free response. This is because I told the class I would be putting this second problem on test. I reviewed at least one practice problem just like it in person (and I believe I did two, actually) and I posted another document on the exact same thing. I told everyone I'd be doing this, and I'm sticking to my word on that. 28% of the class followed through on me saying this, and they prepared and got rewarded.

MORE Final Exam Information and Practice

 

A problem is presented on the Introductory page of the attachment. Its answer is 9680 m/s.

 

And a Chapter 5/6 study aid. Solution breakdown of something specific.

 

Projectiles. This file is amazing. Its key (on the latter pages) is a festival of alternative methods to be used for checking understanding. So don't look at any of the key until you've done the entire practice document.

 

That's it for the helpful final exam postings. The two January 15 postings and the January 7 posting. I feel closure.

Conservation Laws Practice - Deciding conceptually what to conserve (if anything) is heavily on the final. Chapter 6 problems provide mastery practice in this, especially problems like 33, 50, 56, 58. Attachments here are related to those specifically. 56's attachment is elsewhere online.

 

50 and 58 are both even, so you'd like their answer since the back of your back lacks that. Both problem's answers are in my attached document for 58.

Final Exam Info

 

Here is a start, attached files.

 

Jan. 6 info: You should be on the following site a lot:

 

 

It has four years of sample Free Response problems. So that's close to 20 problems. Take them like they are tests. And then use the scoring guidelines to grade your own. I use problems like this as ideas for my own final.

 

The exam will cover Chapters 1 through 6.

Class notes from Tuesday 12/18: This is to help you know what's going on so you can perform well in class on 12/20, when you'll be challenged to collect the best data set possible for credit.

 

Informal ballistic Pendulum: Can was about 100 g, dart was about 2 g, can with dart in it went about 7 cm sideways during the swing. The length I had called L was 45 cm.

 

Problem to solve: Hypothesize about what quantities are conserved and when in the process of the dart entering the can at high speed, the can colliding with the dart and them sticking together, and then the two of them swinging to the highest point in the pendulum.

 

For example, there are a few very specific energies and momenta that you can calculate. Start doing so. If you watch this space between now and Thursday, I might add to it. For example, I could add the hint, calculate the number of Joules of PE gained as the dart/can swings from the low point to the hight point in the pendulum.

 

Another example: Is it reasonable to take that last potential energy mentioned above and set it equal to half of dart mass times the square of launch speed? If you did, it would look as follows:

 

(1/2)(0.002 kg)*v*v = (0.102 kg)(10 m/s/s)(height risen in the pendulum)

 

Get that height rise, plug it in, and see what the dart launch speed v would end up being as a consequence. If that speed is unreasonable, then the conservation assumptions that lead to it are bad assumptions.

Due Tuesday Upon Arrival - Collision Pattern Summary Assignment 2018. Everyone has to come up with three sets of results, one for each collision type, so read carefully. This was shown in class. It was agreed that each student's individually assigned numbers would be found in the charts of the electronic file.

 

This is a self-explanatory document and set of tasks, especially if you follow the example file named "Collision Pattern Summary Assignment 2017 - Solved Example"

Full Solution to a Mock Test handed out in class for Chapter 5

 

Another very thorough Practice Quiz with solution

 

References to More Book Practice - on the Study Guide

Due Date: Leg Power and Human Energy Expenditure Solution (to all items on the assignment sheet) is due upon arrival on Monday Nov. 26.

 

The instructions remind one of how to show defended responses. (Answers have to be defended with work shown, and no units means no credit.) Suppose a person asks, "Is this just answering the worksheet or is this a lab report?" The person asking that would do better to realize that SOLUTIONS to the worksheet with work shown is the same thing as doing a lab report. Either way, one has to defend responses by showing work. And it always goes without saying that Data reporting is the first thing reported on the entire graded paper. There's insufficient room to write these things on the assignment worksheet so those who hand in that will have their work not credited. I shouldn't be saying these things in November. A person is supposed to use one's own judgment to already know how to figure out the things above, because that person's priority would be to communicate to the reader how results are obtained.

 

Your Thanksgiving present is the attachment. It's a way to check if one is doing this correctly. It says Running the Stairs Key. It's Bleachers actually, but it's the same thing. And when you're done, you can relate your results to your Thanksgiving meal.

 

The original assignment file is attached, but it was handed out in class. filename: Running the Stairs.

Very Last Practice Test - Posted here at 6:20 on 11/7. Given the late hour*, this is designed to be taken quickly, corrected, and you move on. Don't spend time debating and fretting over it. It's not posted to encourage cramming. Nobody should be last-minute cramming There's no time for that, and it doesn't work. This post is for fine-tuning of how you communicate in solution form. The file is named Timed Quiz.

 

*Keep in mind, nothing I've posted since November 6 is essential for teaching this material. It's all just icing on the study cake. I don't recommend studying or practicing past bedtimes.

 

New and Improved Rubric for Test 17 Free Response 2 was posted 5:45 PM on 11/7.

 

Nice Practice Test Problems - see attachments

 

And from the book:

Any odd ones

And a few favorites of mine: 53, 55, 57, 59, 63, 65, 68, 69, 73, 77

 

 

Free-Body Diagram Concept Quiz on Tuesday October 23 - this was mentioned in class, and I also said I have some good Diagnostic Tools you can use to quiz yourself:

 

#54 from the AP Physics C Book - should be old news by now. But posted here in case you fell behind. The Problem Statement document is because I'm assuming you don't have that book. I diagrammed it well and stated it in a word document. But its key, the "Perfect FBD's" document is the very thorough discussion that everyone is to have read by now.

 

Tutorial 2 - This is your chance to see if you are actively applying the discussion you were to have read in "Perfect FBD's for ... #54". I wouldn't use this Tutorial 2 problem without first having done 54. This Tutorial 2 might be old news by now for a lot of people.

 

Tutorial 1 - This is new, actually easier than the stuff above. I thought I'd throw it in there. This one isn't a great diagnostic for the Free-Body Diagramming skill, but it's a currently relevant problem.

 

"Quiz Purely on FBD's" - the new one, the Master One! In six separate documents! Take them in this order:

First is "Quiz Purely on FBD's" followed by its key.
Second is "Quiz Purely on FBD's Follow Up" followed by its key.
Third is "Quiz Purely on FBD's - Numerical Solving" followed by its key.

 

Please note that the heavy algebra culmination of "Quiz Purely on FBD's - Numerical Solving" does get beyond the scope of what I'll be asking on the quiz of 10/23. That quiz centers around the FBDing skill and the concepts of Newton's Third Law and Newton's Second Law.

 

Finally, it's good to have some familiarity with the inclined plane to tackle "Quiz Purely on FBD's". So a write-up of my in-class discussion of that is posted here as well. It has the mysterious title "Concrete Example of the V I Method."

 

 

"Tutorial 2" full file.

 

You were given the first two pages of this in class. Do those two first two pages exactly as it says BEFORE opening up this file. This file also contains Pages 3 through 7, which will begin to give away answers.

 

The Perfect FBD Strategies is what the first two pages refer to as a checklist.

 

Note: The file name says Chapter 5. It's actually Chapter 4 for your Period 2 class.

 

This is posted for the benefit of two people who told me they'd be absent on Wednesday 10/17, but it's a good exercise for anyone.

Two things due 10/15:

 

1. Your effort to make three perfect Free-Body Diagrams of the three masses in Other Book Chapter 5, #54. You copied down this problem in the classroom.

 

1A. Compare the three diagrams you made to the checklist document attached here called "Perfect FBD Strategies".

 

1B. After you make the three Free-Body Diagrams as perfect as your visualization tells you to, finally check things over with the key document attached here called "Perfect FBD's for Chap5 #54".

 

2. Use these FBD'ing skills on the Practical Solution document called Tutorial 1 that's attached.

 

If you have time to work ahead, all of Chapter 4 could be understandable to read and work through at your own pace after you have done what's described above. I wouldn't do it in the reverse order though.

Period with the closest match between theory and measurement in the "a = F/Mass" experiment?

 

Period 3!

 

Any student can study their results file (attached) and learn some things. See if you can figure out the connection between the slope of each graph shown and the constant that is stated in the graph's title. (On each graph, the slope is stated clearly in the y = mx + b format.)

 

In the Objective 1 graph, the comparison between graph slope and the number in the title is more obvious. In the Objective 2 graph, there is still a clean connection between graph slope and the number in the title, but you have to do something mathematically to see it. See if you can figure it out.

HW Due Monday: I am checking, so bring the completed worksheet and be prepared for my silly comprehension question that I'll ask.

 

I very much appreciate Period 2 getting good stuff done while I (and the rest of the science department) had to be pulled away for district meetings. So you might have gotten all done in class. Here are a few attachments for you to be extra sure that you got the main idea and be prepared for whatever silly thing I might ask you to do in class on Monday 10/1.

 

The Planetary Data Chart isn't really necessary to give you. You could always look up such a thing. It's just here for your convenience, should you want to practice more in accordance with the advice of the other two attachments.

 

And finally, I've also attached the original HW document in case anyone was absent and did not get one in class.

Homework reminder before Tuesday 9/25:

 

It's OK if you don't have Experiment 2 written up, but I'll start accepting them, since Exp. 1 has been returned to you. (No one seemed worried about the notice on the side board that says to hand in Experiment 2. The thinking there was that it's pretty much done, and there isn't much to do at home. But if I'm wrong, I didn't want you to worry about two assignments, since you are already doing the "Mass is Not Force, Weight is Force" packet.)

 

As I explained in class, one thing you DO have to do by 10 AM on Tuesday 9/25 is the Mass vs. Weight packet that is posted here. It's title is "Mass is Not Force, Weight is Force". (I also explained that I would give any individual a printout if they didn't want to print it from the internet at home. Such people would need to see me in person.) But is weight really force? We approximate that it is. But some people think weight is the curving of spacetime. If you remind me, I'll show you a neat little video about that on 9/25.

 

The correct final answers from the different versions of the quiz:

 

Depending on whether the given initial speed was 54, 48, 42, or 36 m/s, the answers were:

 

2. 3 s, 2.83 s, 2.65 s, or 2.45 s

3. 108 m, 90.5 m, 74.1 m, or 58.8 m

4. 5.19 s, 4.90 s, 4.58 s, or 4.24 s

6. -36 m/s/s, -33.9 m/s/s, -31.7 m/s/s, or -29.4 m/s/s

Quiz Wed. Sept. 19

 

The practice for it has been happening; several solving items on the topic have been offered in class. The attachments here offer more.

 

Chap 2 Study Guide: This is simply a list of odd-numbered book problems that reinforce the same kinematics skills that have already been offered in class. Any individual student can decide how many of these would be useful for more strength-building. There are answers in the back of the book to these odd problems, so that one can self-monitor. Some of the book problems are more complex-looking than others, but all can be picked apart and solved through the use of a velocity versus time graph, as taught in class.

 

A solution document to Real Quiz 1 will be given to people as hard-copy during the Period 2 on Monday, 9/17.

 

A mistake is for a student to run across a challenge, as signified by a particular book problem, like say #49, and say, "Oh, this is going to be hard." The person who jumps to that conclusion doesn't know if it will be hard or not. Read why: All of these problems require interpretation; that doesn't mean their content is "hard". The need for interpretation means that if interpretation is not done, then the problem remains impossible, just like trying to navigate from road signs in a foreign language is an impossible task if one does nothing to learn the new language. Once the proper interpretation is done, the problem is seen to be simple. Make the interpretation effort before reaching the conclusion that "this is hard" or "I can't solve this on my own." An example of interpretation is getting used to reading a velocity versus time graph to simplify a problem like #49. I have written a document that reminds everyone how a velocity versus time graph can be used for Problem #49. That document is attached to this message. See what you would honestly do on your own for #49, see how far you get, and then work through my document with the Solution Outline for #49.

Big Bang Theory Quiz Prep Problem:

 

"Lois Lane is falling with an acceleration of 9.8 m/s/s. She then encounters Superman when her speed is 120 mi/hr. He decelerates her in a space of 2 feet. Numerically prove why this would kill her."

 

Related question: In class you were asked to identify how many of the kinematics quantities were told to you as Givens in the Big Bang Theory scene as quoted above. The answer was six quantities were told to you. That's six of ten. Which six? (And why are there ten possible quantities? - the reason there are ten was stated in class. Make sure you know that conversation.)

 

Another way of answering why the deceleration in 2 feet is so dangerous is to answer the following: Which quantity (distance, initial velocity, final velocity, time, or acceleration) is it whose extreme value will reveal danger for Ms. Lane. Solve for that quantity, given that the stopping distance is only 2 feet

.

Scroll down to see the answer for what to solve for, but try to answer on your own first...

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Answer to the question, "What are you solving for?":

Use kinematics to solve for acceleration in Phase II. Phase I is her free-fall motion; Phase II is Superman slowing her down. The six givens in the story are the following:

 

a - Phase I = 9.8 or 10 m/s/s

vFINAL - Phase I = 120 mi/hr

vINITIAL - Phase I = 0           hidden given

 

displacement - Phase II = 2 feet

vINITIAL - Phase II = 120 mi/hr

vFINAL - Phase II = 0          hidden given

 

From the above six givens, any of the following remaining quantities could be solved for:

 

distance traveled in phase I

time it took Lois to end up moving at 120 mi/hr

 

acceleration during Phase II

stopping time during Phase II

 

The attached document will reveal the answer and the solution for the acceleration in Phase II. It's a concise, well-organized 1-page solution which talks about concepts, not just formulas.

The Virtual Version of Exp. 2 Data

To make sure you're caught up, if you are in Period 2, work on this problem: Given that the event seen in this position versus time plot was a vertical launch of unknown speed, it took 3.2 seconds for the ball to reach its highest point in the motion. Use that fact and the position versus time data chart to figure out the exact launch speed at t = 0. (Note: you are not given the acceleration; this is a virtual planet that's not earth, but the ball is in free-fall.)

 

If you're in Period 1 or 3, this would be for working ahead.

An Example of how to make a good lab write-up

Due 7th - To fill in the Instantaneous Velocity versus Time chart that I gave you in class.

 

The file attached here is the electronic version of the hard copy I handed out. Should be VERY helpful.