Final grades

I've just posted your final grades on myBama, and I just updated the gradebook on Blackboard to include your final exam scores and overall averages. Have a look.

The final exam average was about 80%. For the problems portion you averaged 78.9%, and for the multiple choice you averaged 79.5% after scaling. The problems section went well, and there was no scaling. The multiple choice section went ... less well. The raw average was in the 60% range, so I scaled it by taking your best 9 out of 12 multiple choice questions and adding 7% (with a maximum of 107% on this section). The average of the multiple choice and problems sections then determined your final exam grade, and the class average was about 79.2% for the final exam as a whole, with a standard deviation of 13%.

Quite a few people changed grades (like B+ to A- and vice versa) as a result of the final. Many went up, many went down. On average, your final exam grades were about 2% lower than your average going into the final. Not many of you changed by more than half a letter grade, but some of you did. Those are the breaks, and I really hate doing it. Assigning final grades is agonizing, even when it is basically just by-the-numbers, and even after all the scores are in and the grades calculated it takes me hours to pull the trigger and submit grades.

In the end, the overall class average was 85.5% with a standard deviation of 8.65%, which is quite high. Most of you got A's and B's, and I'm fine with that.

I know some of you will be oddly surprised by a higher-than-expected grade, but a good number of you will also be annoyed by a lower-than-expected grade. Look at your final exam scores and overall grade breakdown on BlackBoard, and keep in mind that the final exam was worth quite a bit (so it was possible to change your grade by a fair amount).

If things don't seem to add up, or you have questions, let me know ASAP - we have just under 24 hours to easily alter things before the deadline if a mistake is found. 

Final grades are not ready yet

Those aren't the final grades on Blackboard - I'm still not finished grading the final exams. I should have the finals graded by the end of the day, and hopefully I'll have final grades calculated this evening.

I'll post here when the grades have been updated so you know for sure, and I will also include a column for the final exam score on Blackboard.

Final exam layout

The final exam will be broken up into 5 sections. In each section, you will have a few required multiple choice questions and a choice of problems (4 problems given, solve any 2). The multiple choice questions will require some calculations, but will be much shorter than the problems. Here are the details of each section, with the corresponding sections of the book noted.

Overall, you need to do 10 problems and 12 multiple choice questions. An extensive formula sheet will be given, and you will be allowed to bring in two sheets of paper (front and back) with your own notes.

Section 1: Kinematics

• 2.2-10 (1D motion)
• 4.2-7 (2D motion)
• 5.2-9, 6.2-5 (forces)

2 required multiple choice questions, choose 2 of 4 problems

Section 2: momentum and energy

• 7.2-8 (K, work)
• 8.2-8 (PE, consv. E)
• 9.2-10 (p)

4 required multiple choice questions, choose 2 of 4 problems

Section 3: rotation and gravitation

• 10.2-10 (rotation)
• 11.2-4, 6-11 (torque, angular momentum)
• 13.2-8 (gravitation)

1 required multiple choice question, choose 2 of 4 problems

Section 4: oscillations and waves

• 15.2-7 (oscillations)
• 16.2-10, 17.2-5 (waves)

2 required multiple choice questions, choose 2 of 3 problems

Section 5: fluids & thermodynamics

• 14.2-10 (fluids)
• 18.6-11 (temperature, heat)
• 19.3-5, 11 (kinetic theory of gasses)

3 required multiple choice questions, choose 2 of 4 problems

Exam 4 and its solution

Here is exam 4 and its solution. Though it was an optional exam, it is a reasonable guide to what sort of questions I might ask about oscillations and gravitation on the final.

Details of the final exam coming soon.

Exam 4 is cancelled

If you were in class on Wednesday, you'll recall I cancelled exam 4. I think we've had enough exams at this point, and I'd rather spend the rest of our time on finishing the rocket competition and getting through the remaining material on thermodynamics. So, there is no exam Friday.

What this means is that the first three exams and the final will be weighted proportionally more. Specifically, that means the first three exams are worth 12.5% instead of 10%, and the final is worth 22.5% instead of 20%.

If you were relying on exam 4 to bring up your grade, please talk to me. I will give you the option of taking an optional exam 4 next week if you would rather proceed according to the original syllabus (4 exams worth 10% each and a final worth 20%).

Exam 4

Exam 4 is this friday. Since it is only a 50 minute exam, it will be short. I will confine it to chapters 13 and 15 (gravitation and oscillations, respectively). It will be (most likely) 5 problems of which you have to solve 3.

You may safely neglect the "Einstein and gravitation", "Kepler's laws"sections as well as the "Damped simple harmonic motion" and "forced oscillations and resonance" sections for the purpose of this test, but possibly not for the final.

This week we'll talk about waves a bit more, and next week we will finish up the course talking about heat and thermodynamics.

Formula sheet for exam 3

Here is a draft formula sheet for exam 3. 

Exam 2 solutions

Exam 2 solutions are available. You'll get the exams back at the start of Wednesday's class.

HW 3 solutions / Exam

HW 3 solutions are out. Reading them carefully would be a good way to study ...

As a reminder for tomorrow's exam, you are allowed 1 sheet of standard paper (front and back) with notes. You'll also be given a formula sheet that should have everything you need, a draft of which is here.

Class for Wed 19 Feb / upcoming exam

We'll continue our discussion of momentum a little bit, time permitting, at least as far as figuring out how to handle collisions. A larger portion of the class will be related to homework problems, which are directly relevant for the exam, and another lab on programming.

For the homework, you should be a little bothered by #6, I'll outline 2 methods to solve this one. Number 7 should be quite mysterious, and that is OK - the technique you need to solve it is related to the experimental propagation of uncertainty - if you change one variable a little bit, how do the others change? This is related to how you move along surfaces in 3D, something you are learning or have learned in Cal III.

Number 8 requires some thought - the equilibrium spacing is where U(r) is minimum, or where dU/dr = -F = 0 and the net force is zero. Find this first. The breaking point of molecule is when you exceed the maximum restoring force implied by U(r). If you find F(r) = -dU/dr and look for its maximum, this will occur for a particular r, beyond which the force binding the atoms together is exceeded and the atoms will come apart. Mathematically, that means setting dF/dr = 0 to find the maximum, that's the radius beyond which you break the molecule. Using the result for the equilibrium spacing, you can write it in terms of only n, m, and the equilibrium radius. I might have asked this question before if you are willing to dig a little.

For the exam, the format is exactly like the last time. It will likely consist of 6 problems, of which you have to solve 4. The questions will only be on work, kinetic energy, potential energy, and conservation of energy - 2 chapters in the book. You'll have a formula sheet given like last time, and can bring 1 sheet of paper of your own. I will post HW3 solutions by Thursday morning, hopefully, to help you study.

Finally, the lab: we'll continue with coding. You have two basic tasks.

1) I assert that the sum of the first n cubes of integers (sum of i^3 from i=1 to i=n) is the square of the sum of the first n integers (square of the sum of i from i=1 to i=n). Write a program that can check this for specific values of n. Print out your code and results for n=10 and n=17. Basically: sum the integers, square the sum, and compare to the sum of the cubes of integers.

2) Write and evaluate a program to calculate the range of a projectile under only the influence of gravity (no drag forces). Verify that it gives the correct result (within a few percent numerical error) for a launch speed of 25 m/s and a launch angle of 45 degrees. (You already know how to calculate the range without a drag force ...) Note that links I gave previously, and specific folders here are highly useful. Print out your code and note your results for the conditions noted.

Exam 1 solutions

Here you go.

I've also posted the solutions to your quizzes so far.

Formula sheet for exam 1

The formula sheet I'll give you tomorrow will look a lot like the one I used last time I taught PH125. A few things to note:

• The exam was later last time, so there are a few things on the formula sheet we haven't covered (drag force, curved paths)
• I will add at least the trajectory y(x) for a projectile launched from the origin (in addition to the parametric x(t) and y(t) equations already there. 
• You can still bring in 1 sheet of your own in addition to what I provide. 
• Don't forget to bring a calculator tomorrow. Check the batteries.

Exam 1 details

As you may be aware, exam 1 is Monday during our usual class time in our usual classroom. While this is a 2 hour class period, I am designing it to be a 1 hour exam. You will have 2 hours if you need it, but if you finish in an hour (like I hope) you can just leave early.

Here are the sections from the textbook covered

• 1D motion (2.3-2.9)
• 2D motion (4.2-7)
• Force & motion (5.2-9, 6.2-3, 6.5)

There will be 6 problems in total, of which you must complete 4. If you do more than 4, I will grade them all and use the best 4 (but try to get 4 done well first). There will be a formula sheet provided with all the basic formulas and any numerical constants you will need, and you can bring in one sheet of 8.5x11in paper of your own with notes, etc. What you put on the one sheet you bring in is entirely up to you, and you can use the front & back of the sheet.

There will be heavy partial credit on the exam, so show all your work and be as clear as possible about what you are trying to do.

Good things to study? Old homework and exams, and the homework problems I've given you so far. The exam questions will be easier than the homework I've given you, so don't worry too much. Doing the example problems in the book, or the odd numbered end of chapter problems is also good (so you can see the answer when you're done).

I'll be posting HW2 solutions shortly.

The Snowpocalypse continues

We'll have to play this by ear, but here's the current plan:

• HW due Friday by midnight, presuming UA is open Friday. 
• Friday's class: work homework problems, review for the exam. 
• Exam on Monday, but taking only ~50 minutes. We'll spend the rest of the class period working problems and discussing new material.

Given that it is supposed to be in the high 40's tomorrow at least, I fully expect we'll have class on Friday. I don't think we'll know whether UA will be open tomorrow (Thurs) until ~4pm today.  UA is closed Thursday. Presuming we have class on Friday, we'll spend most of that time working on homework and getting you ready for an exam on Monday.

Exam duration / syllabus confusion

The syllabus is not totally clear as to how long the exams are. The in-class exams will all be 50 minutes long, no matter what day they occur on. 

There is some confusion because my original (internal) schedule had all the exams on M or W, presupposing rather long exams. After rethinking it a bit, the exams didn't end up coming at natural logical breaks in the course material, and of course long exams just suck. At that point, I moved the exam dates around, putting most of the exams on Friday instead (so long as there was a natural conceptual break in the material), but forgot to update the syllabus. (One exam remains on a Monday because the preceding and following Fridays would make for awkward exam coverage.)

What the syllabus should say is that all four "hour" exams will designed to take 50 minutes, independent of what day they are on. For the one exam scheduled on Monday, you will still have a 50 minute exam, not a 110 minute exam. We will probably use the remainder of the 110 minute class period to review or do a short lab.

Final Exam

Your final exam is here, if you want to look back at it ...

Also, moodle is now up to date with everything except the final exam. Labs 9, 10, and 11 were from the rocket competition:

L9 = competition performance
L10 = quality / correctness / cleverness of code
L11 = quality / cleverness of the physical setup and measurement system

FYI, the grading breakdown (weighting, number dropped, etc.) can be found here.

Formula sheet

Here it is.

Draft anyway; some proofreading remains.

Review Session TONIGHT

Room 203 Gallalee, the usual classrom, 6-7pm.

Come bearing questions ...

Final Exam

One of you asked about the final exam details. Below is what I said.

The review session will be Monday evening, I'll post here when it is finalized. I'll also provide the formula sheets, probably on Sunday, along with more detail. It will be easier than any of the other three exams I gave ...

It is going to be a larger number of much easier problems, much like the example problems in the chapters. Only chapters we covered in class are on the exam, and nothing we covered after exam III is on the exam.

It is going to be something like 8-10 fairly easy problems that you need to solve in about 15 minutes each, rather than the 4-6 hard problems that take 30 minutes you had on the previous exams. You will have a choice of problems, so it is reasonable to skip over a couple of chapters and just not choose problems related to them.

My suggestion would be to try to solve the sample problems without looking at the solutions at first. Basically, the exam will reward knowing the basics really well. I will try to make the problems very similar to the level of practice problems. After that, I would try the problems on the sample tests I posted - mostly easier problems than we have been doing.

You'll get a formula sheet which is fairly comprehensive. I'll try to post it as soon as I can, but it might be Sunday before I get it done. It will be a combination of the formula sheets from the first three exams. You can bring in two sheets of paper with your own notes.

Exam III solutions

Here you go. Let me know if you find any errors.