8.01L - Physics IFall 2015

Lecturer: Prof. Alan Guth
Recitation Instructors: Prof. Richard Milner, Prof. Min Chen, Prof. Pablo Jarillo-Herrero
Lab Instructor: TBA
TA: Lina Necib

Class Schedule

         
Physics 1 R01 TR 9:00 Milner Room 32-082  
Lecture MWF 11:00 am Room 6-120 R02 TR 10:00 Milner Room 32-082  
R03 TR 11:00 Chen Room 32-082  
R04 TR 12:00 Chen Room 32-082
R05 TR 1:00 Jarillo-Herrero Room 32-082
  R06 TR 2:00 Jarillo-Herrero Room 32-082

Announcements:

MON 02/01/2016: Final Exam Solutions are posted
Dear 8.01L Students,
The Final Exam Solutions are now posted on the Exams tab of the course website.
— Alan Guth —

SAT 01/30/2016: Information about course grades
Dear 8.01L Students,
Last evening I posted the numerical averages of your grades on the Gradebook, and for most of you the letter grade has also been decided and posted. I have now also posted, on the Exam tab of the 8.01L website, a histogram of these total average grades, which shows the letter grade cuts that were used.
The total average grade combines the four term exams (40%), the final exam (30%), the problem sets (20%), lecture and recitation attendance (3% each), and the labs (4%). After the numerical grades were calculated, students slightly below borderlines were discussed individually by the course staff, and were sometimes boosted above the borderlines. Students whose grades have improved significantly during the term, and students whose average has been pushed down by a single low grade, were the most likely to be boosted.
The lecture attendance grade, by the way, was based on the clicker responses for the 29 lectures for which I had recorded data. It didn't matter what you clicked, but if you clicked at all you were counted as present. I allowed everyone two free excused absences, so your grade was the number of lectures for which you clicked (or were given an excused absence) plus 2, divided by 29, and then times 3, with a maximum of 3. The recitation attendance grade was assigned by your recitation instructor, and is based on how often you attended. If you switched sections, both recitation instructors were involved in assigning your grade.
I'll get back to you during the coming week to let you know how you can get back the problem sets that have been graded but not returned, and how you can see your final exams. I will also let you know when I post the solutions to the final exam.
Best wishes,
— Alan Guth —

FRI 01/29/2016: Please fill out course evaluations
Dear 8.01L Students,
There are only 2 1/2 more hours for you to fill out the course evaluations. The deadline is at 5:00 pm today. The staff and I very much appreciate your feedback, so we hope that all of you will take a few minutes to respond. I know that many of you filled out the evaluations in December, but since this course ends in January, it is the January evaluations that have the most meaning.
You can find the forms at
http://web.mit.edu/subjectevaluation
Thanks loads!
— Alan Guth —

THU 01/28/2016: Final Exam scores are now posted
Dear 8.01L Students,
Your final exam scores are now posted on the Gradebook, so you can see how you did. I also posted a histogram on the Exams tab of the course website, which shows a conversion into letter grades. And the Final Exam itself is also posted on the Exams tab, so you can remind yourselves about the questions. I hope to have solutions posted by tomorrow.
The average on the exam was 62.7. Problem 5 was the problem taken from the Problem Sets, and it had an average score of 71.7. In the previous two exams the average grades on the homework problems were 61.0 and 66.5, respectively, so the trend looks very good! But I would be happiest if you averaged 95 on the homework problem, but alas the course has ended, so I won't be able to see that happen. But you can continue your efforts in other courses. Many of you did learn how to do the homework problem: 5 of you got it perfectly, and 23 of you scored 25 out of 28 points or above (89% or above), so that's great.
Problem 4 was a little novel and hence difficult, and it had an average of only 45%. The most difficult part, part (d), had an average of only 20%. But it was not as hard as it may have seemed, if you kept your wits about you. On part (c), for example, where the average grade was only 38%, all you needed to realize was that there were no forces on the rod in the horizontal direction, so the x-coordinate of the center of mass, initially stationary, would remain stationary.
On the whole the staff and I thought that the exam was on the easy side. For example Problem 3, the banked curve problem, was on last year's final exam (which you were given as a model), it was #2 on the list of Top Ten 8.01 problems, and Richard Milner did it as an example problem in his review. Yet the average on it was only 67%. Apparently you folks mostly thought the exam was on the easy side, too, since only a handful of you stayed the full three hours. So, I have to admit that I was a little disappointed by the average on the exam.
When you look at the histogram, you will see that there are a number of people with grades below what the staff and I consider passing. I do, however, have some good news concerning that issue. Most of the people in this category have done better work earlier, and the final exam counts only 30% of the total grade. Most of the people who did not have a passing grade on the final exam will still have a passing grade for the course. I expect that we will be able to post final grades on the website by late tomorrow afternoon.
The course is currently open for evaluation, and I want you to know that we very much value your feedback. Please fill out the evaluations. You have until tomorrow afternoon at 5:00 pm, but please do it as soon as possible, so that you don't forget about it.
As I said at the end of the last lecture, I really enjoyed teaching this class, because you folks have been very sharp. You have caught me in lecture when I have made mistakes on the blackboard, and you have asked very good questions all along. I have enjoyed getting to know some of you at office hours and at dinners with some of you, and I think that like MIT undergrads in general, you are a terrific group of people.
Best wishes for the rest of your stay at MIT and beyond.
— Alan Guth —

SUN 01/24/2016: Error in the solutions to 1(d) in last year's final exam
Dear 8.01L Students,
It has been called to my attention that the solutions to last year's (2014) Final Exam, posted on our website, have an error in the solution to Problem 1(d). It is correct up to the last line, but in the final step a factor of R was dropped. The right answer should be
      alpha = (2/3) (g/R) sin theta
Again, best wishes for tomorrow's exam, where we hope that neither your solutions nor the ones that will later be posted will contain any errors.
— Alan Guth —

SAT 01/23/2016: Min Chen's review tomorrow; Error in Pset 13 solutions
Dear 8.01L Students,
From what I hear Richard Milner's review session today was a big success. The notes that he prepared for this session were emailed to all of you, but they are also posted on the "Exams" tab of the course web page. They look excellent.
Tomorrow Min Chen will be having a second review session, at 2:00 pm in Room 36-112. He describes the plan as follows:

 
  "I will complement Richard's nice review of deriving every formula, by starting from a simplified set of formulas to work out examples of problems which I selected from 8.01L web on Thursday night. I will further add a twist or variation to each problem to bring it to a deeper level than the solutions. So my review could be considered as a continuation of Richard's."
 
Also, it has been pointed out that there is a typo on the Problem Set 13 Solutions. Eq. (3), in the solution to Problem 13-1, should end with "+ m L^2 / 2", while it is shown erroneously as "+ m L^2 / 4". I'll post a revised problem set solutions later tonight to fix this problem.
Again, best of luck for the final exam and beyond.
— Alan Guth —

FRI 01/22/2016: Review Session Update; Pset 13 Solutions posted
Dear 8.01L Students,
As most of you know, our staff will be holding two review sessions this weekend:

  • On Saturday, Richard Milner will be running a review session at 2 pm, in Room 4-237.
  • On Sunday, Min Chen will be running a second review session, at 2 pm, in Room 36-112.
You also may want to know that the solutions to Problem Set 13 are now posted.
Best wishes, and good luck on the final exam.
— Alan Guth —

THU 01/21/2016: A possible additional review session on Sunday
Dear 8.01L Students,
When we discussed the timing of the review session for the final exam, it turned out that there were many conflicts for any of the possible times. For that reason, Prof. Min Chen has volunteered to run an additional review session on Sunday afternoon (1/24/2016), from 2:00 to 4:00 pm, if there is enough interest. So, if you are interested in attending such a review session, please reply to this email to let me know.
If there is not enough interest, then this review session will not be held. I will let you know by email in either case.
Best wishes,
— Alan Guth —

WED 01/20/2016: Extended office hour today
Dear 8.01L Students,
With the final exam coming up soon, today I will schedule another extended office hour, from 1 pm to 3 pm, in my office, 6-322. The goal will be to work problems, mostly from the homework, to sharpen problem-solving skills.
— Alan Guth —

MON 01/18/2016: Formula sheet and practice problems for the final exam
Dear 8.01L Students,
Exam 4 and its solutions, as well as a grade histogram with estimated letter-grade cuts, were posted yesterday morning. Practice problems for the final exam were posted last night. And this morning I posted the formula sheets for the final exam. These formula sheets are really intended as a summary (15 pages) of the course, so I hope that you will find them useful in studying. The bottom line is that you should now have all the materials that you need to study for the final exam.
On Exam 4, the class average on Problem 3, the one that came from the problem sets, was only 66.5%, which seems to indicate that most of you are not learning how to do the homework problems. We have tried to give you very detailed and explanatory solutions to these homework problems, but of course some of the problems are hard. If you have trouble figuring out the solutions to the homework problems, then please come to tutoring or office hours to ask about them. I really think we can help.
There will be a review session for the final exam on Saturday (1/23/16), at 2:00 pm, held by Richard Milner. It will probably be in 6-120, but that still has to be confirmed.
Since today is a holiday, I will not have my usual Monday office hour, but instead I will have an office hour tomorrow, Tuesday 1/19/16, at 4:00 pm, in my office, 6-322. Since it is the last week of classes, I will make it an extended office hour, from 4:00 - 6:00 pm.
For those of you who are interested, I have also posted a proof of the angular momentum center-of-mass decomposition --- that is, the theorem that I stated last Wed in lecture, and reviewed on the slides for Friday, which says that the angular momentum of a rigid body that is both translating and rotating about an axis of symmetry can be written simply as the sum of two terms. One term is the angular momentum of a point particle whose mass is the total mass, with the position and velocity of the center of mass, and the second term is I*omega, describing the rotation about the center of mass. You are not responsible for the proof of this theorem, but for those of you who are interested I have posted a proof on the Lecture Materials page with Lecture 39. (You are responsible, however, for learning how to use the theorem, and there is one problem on this week's problem set that explicitly asks you to do that.)
— Alan Guth —

THU 01/14/2016: Problem Set 13 is now posted
Dear 8.01L Students,
Problem Set 13 is now posted, so you can start on it whenever you are ready. There are 10 problems, plus two Super-Challenge optional problems, that you can do if you want for up to 10 extra credit points each. The pset is due on the last day of classes, Fri Jan 22, at 11:00 am.
— Alan Guth —

TUE 01/12/2016: Please attend your usual lab today
Dear 8.01L Students,
There are no recitations today, but we still want all of you to come to the lab session that you regularly attend. Otherwise there is a danger that the attendance could be unbalanced, and then there would not be enough experimental setups to go around.
Thanks a lot.
— Alan Guth —

MON 01/11/2016: Recitations cancelled tomorrow, Tuesday Jan 12
Dear 8.01L Students,
Since we expect that you will all be tired tomorrow after the exam tonight, and since there is not yet another problem set to discuss, we have decided to cancel recitation sections tomorrow. (There will still be labs tomorrow, however --- don't forget the labs!)
If you have any last-minute questions while studying for the exam tonight, you can drop into my office hour at the usual time, from 4:30 to 5:30 pm.
Good luck on the exam tonight.
— Alan Guth —

SUN 01/10/2016: Final Problem Set 12 Solutions are posted
Dear 8.01L Students,
The final version of the Problem Set 12 Solutions are now posted.
Remember that Richard Milner will be holding a review session this afternoon, at 2:00 pm, in Room 6-120.
— Alan Guth —

SAT 01/09/2016: Preliminary Problem Set 12 Solutions are posted
Dear 8.01L Students,
The Problem Set 12 Solutions are not quite finished, but I have posted a preliminary version, in case you want to get started using it for studying. The preliminary version is missing a solution to Problem 12-3, and the solution to Problem 12-8 is likely to be further edited. I won't be able to get back to it until this evening.
— Alan Guth —

SUN 01/03/2016: Lecture starts tomorrow, at 10:30 am
Dear 8.01L Students,
Just a quick reminder that 8.01L lectures resume tomorrow. For January we will be meeting in the same room, 6-120, but at 10:30 am. Most precisely, the lectures will run from 10:35 am to 11:25 am. There will be no lecture on Monday January 11, due to the exam on that evening from 7:30-9:30 am, and there will be no lecture on Monday January 18, due to Martin Luther King Day.
The other scheduling information for the rest of the course is as follows:

  • Recitations will continue on Tuesdays and Thursdays, from this Tuesday (Jan 5) through Thursday Jan 21. Labs will be held on exactly the same days as the recitations, at 10:00-11:30 am and 12:30-2:00 pm in Room 26-152.
  • Problem Set 12 is due at 11:00 am on Friday January 8, but you should really hand it in before lecture at 10:30. (I forgot to change the due time on the problem set, so it is officially still due at 11:00.) Problem Set 13 will be due at 10:30 am on Friday, January 22.
  • Exam 4 will be on Monday evening, January 11, 7:30 - 9:30 pm in Walker Memorial, Room 50-340 (the usual location). The Final Exam will be Monday January 25, 9:00 am to noon. I am not yet sure of the location of the final exam.
— Alan Guth —

SAT 01/02/2016: Labs start this coming Tuesday
Dear 8.01L Students,
As you know, in January the 8.01L program will be expanded to include labs. There will be a total of 6 labs, which will happen on Tuesdays and Thursdays, January 5, 7, 12, 14, 19, and 21. On each of these days there will be one experiment and two opportunities to do it: from 10:00-11:30 am and from 12:30-2:00 pm. You will be expected to attend one of these lab sessions on each of these days. You should presumably attend the same section on each of these days, unless there is some good reason not to. For most of you --- depending on what recitation you are in --- only one of the two will be possible. The labs will be run by Dr. George Stephans, gsfs@mit.edu.
The first experiment will be on projectile motion, and the information about the experiment has now been posted on the course website, under the "Experiments" tab. You should be sure to read these documents before the lab on Tuesday.
Enjoy what remains of the break, and I'll see you on Monday!
— Alan Guth —

THU 12/31/2015: Problem Set 11 Solutions and Problem Set 12 are posted
Dear 8.01L Students,
Problem Set 11 Solutions and Problem Set 12 are now posted. Unfortunately we are on a tight schedule during January, with Exam 4 happening on the following Monday evening, January 11. For that reason, extensions on Problem Set 12 will be given only for better-than-average excuses.
I'll see you all on Monday.
— Alan Guth —

WED 12/09/2015: Problem 11-4 is incorrectly identified
Dear 8.01L Students,
One of you pointed out to me an error in the identification of Problem 11-4 on Problem Set 11. It is said to be exercise 9.48 of the 13th edition of Young and Freedman, or exercise 9.50 in the 12th edition. It is actually exercise 9.47 in the 13th edition, or exercise 9.49 in the 12th.
I hope this did not cause any confusion. The problem that I want you to solve is the problem for which the text is given on the problem set. If any of you have ignored the text and followed the problem numbers, taking the problem from the textbook, then please let me know. I don't want you to have to do both problems, so I'll arrange for you to get credit for Problem 9.48 (13th edition) or 9.50 (12th edition).
— Alan Guth —

MON 12/07/2015: Time for our lectures in January
Dear 8.01L Students,
Currently the lectures for January are scheduled to take place from 10:30 to 11:30 am, Mondays, Wednesdays, and Fridays. Apparently this conflicts with 6.149, Introduction to Python, which meets at 11:00 am. So, it has been suggested that we might move the 8.01L lecture to run from 10:00 to 11:00, to avoid the conflict.
Tomorrow (Monday) in lecture I would like to take a poll about this (using clickers to be sure we get the counting right). I will put it in the form of two questions:
1) If we move the starting time from 10:30 am to 10:00 am, will this

  • a) open an opportunity for you to take part in some other desired course or activity (where 6.149 is one possibility);
  • b) prevent you from taking part in some other desired course or activity; or
  • c) have no effect on your participation in courses or activities?
2) As a matter of preference, would you
  • a) prefer to switch the starting time to 10:00 am
  • b) prefer to leave the starting time at 10:30 am.
If you cannot come to lecture and would like to cast a vote, you can email your choices to me before lecture.
— Alan Guth —

MON 12/07/2015: Lecture attendance records posted
Dear 8.01L Students,
I have updated the Gradebook to show the lecture attendance records from Week 5 to the present. (There were no records from before Week 5.) Please look over the records. There are some of you who have never successfully transmitted your clicker IDs to the TSG website, and I have sent individualized emails to those people. But there may be others whose clicker ID is recorded incorrectly, and maybe some clickers have malfunctioned. And some of you have told me after class that your clicker batteries have run down --- I have tried to keep track of those pieces of information, but may have sometimes let it slip.
So let me know if the records are not correct.
— Alan Guth —

SUN 11/15/2015: Formula sheets for Exam 3 are posted
Dear 8.01L Students,
I have just posted the formula sheets for the exam. As was the case for Exam 2, the formula sheets are intended to be useful as a study guide, and not just a way of knowing what formulas you don't have to memorize. The formula sheets attempt to summarize all the important relationships that we have discussed so far, so if you understand what is on these sheets, you are in great shape for the exam. Copies of these formula sheets will be given to you as part of the exam.
Let me also remind you of something I said last Friday in lecture: one of the problems on the exam will be based on one of the problems in Problem Sets 7 - 9 (where the super-challenge problem is off-limits).
— Alan Guth —

SUN 11/15/2015: Review session and the fire alarm
Dear 8.01L Students,
Lina Necib tells me that the review session today was cut short by a fire alarm. We apologize for this happening, but it is unfortunately well outside our control.
If you have any further questions, Lina said that you could email her at lnecib@mit.edu, and she will get back to you. In addition, for this week she will move her Friday tutoring hours to Tuesday and Wednesday, from 5-6 pm on each day. Alberto Hernandez will have tutoring sessions as usual on Tuesday, Wednesday, and Thursday at 4:00 pm, and you should also check out the faculty office hours on the website.
Best wishes,
— Alan Guth —

SUN 11/15/2015: Review Session Today at 4:00 PM
Dear 8.01L Students,
There will be a review session for Exam 3 today at 4:00 pm, run by Lina Necib. I'm embarrassed to say that I did not put in the request for a room until 5:30 pm last Friday, and the Schedules Office has not gotten back to us. So, we hope that we can have the review in Room 6-120. Please go there, and if the room is not available, Lina will post a sign on the door to tell you where to go next. I apologize for any confusion. The review is planned for about 2 hours, depending on how many questions you have, etc.
I have just posted the Exam 3 from both 2012 and 2014, along with two extra practice problems from exams of previous years. I will post the solutions on Tuesday morning. Due to the late start of the term, Exam 3 is occurring after Problem Set 9, while in recent years the exam also included Problem Set 10. For that reason, the exams from 2012 and 2014 each have a Problem 3 that involves periodic motion, a topic which we have not yet studied. Thus, please for now ignore Problem 3 on both of the posted exams.
I will be having my usual office hour tomorrow (Monday), 4:30 - 5:30 pm, in Room 6-322.
Best wishes,
— Alan Guth —

SAT 11/14/2015: Review Session for Exam 3 tomorrow
Dear 8.01L Students,
As you know, Exam 3 will take place this coming Thursday, November 19, from 7:30 - 9:30 pm in Walker, Room 50-340.
There will be a review session for the exam tomorrow, Sunday November 15, run by Lina Necib. It will probably be in 6-120, but I'll get back to you about that by email.
Later tonight I will be posting practice problems for the exam, and tomorrow I will post a formula sheet. I finally just posted the solutions for Exam 2. Sorry that they were so delayed, but my trips to Tokyo and Bern made it hard for me to keep up. But I will have no more trips for the rest of the term.
Best wishes,
— Alan Guth —

SUN 11/08/2015: Revised version of Problem Set 9
Dear 8.01L Students,
I have just posted a revised version of Problem Set 9. Problem 9-7 has been replaced by an easier problem, and the old Problem 9-7 has been kept as a super-challenge extra-credit problem.
I also posted the concept question lecture slides from Lecture 24, last Friday. Since we didn't have much time to discuss the questions, this time I posted brief explanations of the answers.
From Bern, Switzerland,
— Alan Guth —

WED 11/04/2015: Supplementary lecture notes about momentum
Dear 8.01L Students,
Today in lecture I did not have time to discuss all the issues that I wanted to: in particular, I did not have time to talk about momentum in a sensible way. Since momentum is a necessary concept for the problem set due Friday, I have written some notes that I would like you to consider an extension of today's lecture. The notes are posted on the course website, on the Lecture Materials tab, with the Lecture Slides for Lecture 23. The Lecture Slides, by the way, include all four concept questions that I had intended to discuss, even though we only had time to discuss two of them.
Sorry for falling behind, but I spent 4 days last week in Tokyo, where I gave two lectures in a world with a 13-hour time difference from ours, and then came home to work on letters of recommendation, Problem Set 8, and Problem Set 7 Solutions (not quite ready yet), among other things. Saturday I take off for another trip, to give three "Einstein" lectures in Bern, Switzerland, coming back the following Thursday. Pablo Jarillo-Herrero will be giving the 8.01L lecture next Monday, and the following Wednesday there is no lecture, due to Veteran's Day. These trips were arranged before I knew that I would be teaching this course, and it was too late to back out. But after I get back from Bern, I will be here for the rest of the course, through January.
Best wishes,
— Alan Guth —

SUN 10/25/2015: Problem Set 6 Solutions are posted
Dear 8.01L Students,
I thought I would let you know that the Problem Set 6 Solutions are posted.
— Alan Guth —

SAT 10/24/2015: Review sessions and postings for Exam 2
Dear 8.01L Students,
There will be an optional, but highly recommended, review session for Exam 2, which will be tomorrow (Sunday) at 2:00 pm, in Room 6-120 with Prof. Richard Milner. It is planned for about 2 hours, but the timing is flexible --- it will depend partly on how many questions you have.
The exam itself is on Tuesday evening, 7:30 - 9:30 pm, in Walker Memorial, 50-340. There will be no calculators.
In addition, I want to let you know about posted materials. I have just posted the formula sheets for the exam, which are intended to be useful as a study guide, and not just a way of knowing what formulas you don't have to memorize. The formula sheets attempt to summarize all the important relationships that we have discussed so far, so if you understand what is on these sheets, you are in great shape for the Exam. Copies of these formula sheets will be given to you as part of the exam.
I have also posted the Exam 2's from 2012 and 2014, which you can use as practice problems. I will post the solutions on Monday, after you have hopefully put some thought into trying to solve the problems, either by yourself or in a study group.
I have also just posted the solutions to Problem Set 5, and hope to post the solutions to Problem Set 6 later this afternoon. The problem sets and their solutions are also highly recommended as a study tool. Lina and I have worked hard in trying to make the solutions pedagogically useful.
Let me repeat what I said in a previous email: When you go over the solutions, it is all too easy to say to yourself "Oh, I know that," and "Oh, I know that, too," etc. Ideally that might be true, but I recommend the following test: imagine that you are sitting next to the dumbest student in the world, and that it is your job to explain to the student every detail of the logic. Go over in your head exactly what you would tell this student.
If you fully understand how to do the problems on the problem sets, you will be in great shape for the exam Tuesday night.
Best wishes,
— Alan Guth —

TUE 09/29/2015: Details about transferring from 8.01 to 8.01L
Dear 8.01 Students,
I'd like to give you a few more details about switching from 8.01 to 8.01L.
First, let me remind you that in order to keep open your option to switch to 8.01L, you should take the 8.01L Exam 1, which is being given this evening, Tuesday Sept 29, 7:30-9:30 pm, in Walker Memorial Room 50-340. You do not need to register for this exam, and you are not making any commitments by taking it. You can just show up, and we will give you the exam and grade it. I should add that for students in 8.01L with conflicts on Tuesday night, we are arranging for them to take the exam at a different time. If any of you would like to take the exam but have a conflict, please send me an email. Let me know what 2-hour blocks of time you have during the day (8 am to 5 pm) on Wednesday. If you have none, then please tell me about Thursday.
If you are taking the exam, be sure to look at our website (web.mit.edu/8.01L/www) for information about the exam. Note that we are not using Stellar. All the files on web.mit.edu/8.01L/www should be open to you except the class contact list; the Busza/Cartwright/Guth Study Guide requires an MIT certificate, but you should be able to access it. If you have any problems with the website, email me.
The exam will cover the material on Problem Set 1 and Problem Set 2. The website includes two practice exams with solutions, and a formula sheet. There will be no calculators. You should be aware that in 8.01L we have discussed uniform circular motion, which I believe is not discussed until later in 8.01.
If you take the 8.01L Exam 1, you will have until Add Date (Oct 9) to decide whether to actually switch to 8.01L. If you do, your Problem Set grades for all problem sets you have handed in will transfer to 8.01L. You will not be asked to hand in the corresponding 8.01L problem sets, but you will need to carefully go over the corresponding 8.01L problem sets, making sure that you know how to do those problems. For Exam 1, your grade for the record will be the higher of the grades that you received for the 8.01 and 8.01L versions of the exam.
Best wishes, and let me know if you have further questions.
— Alan Guth —

MON 09/28/2015: Solutions to practice exams now posted
Dear 8.01L Students,
Sorry that I was late, but there was less time between my meetings than I expected. But the solutions to both practice exams are now posted online for you to study from.
Best wishes,
— Alan Guth —

MON 09/28/2015: Alan Guth's office hour today delayed by 30 minutes
Dear 8.01L Students,
As I mentioned in lecture today, my office hour today will be from 5:00 to 6:00 pm, in the usual room, 6-322. See you then.
— Alan Guth —

SAT 09/26/2015: Review Session, Problem Set 2 Solutions
Dear 8.01L Students,
Let me remind you that there will be an (optional) review session for Exam 1 tomorrow, Sunday 9/27/15, at 2:00 pm, in 6-120, run by Prof. Chen. It is planned for about 2 hours, but the timing is flexible --- it will depend partly on how many questions you have.
In addition, I want to let you know that the solutions to Problem Set 2 are now posted.
When you study for the exam, I recommend that you pay a lot of attention to the two sets of problem set solutions. Lina and I have put a lot or work into making the solutions pedagogically useful. We have tried to explain not just the mechanics of solving each problem, but also how to understand the method in terms of the basic principles.
When you go over the solutions, it is all too easy to say to yourself "oh, I know that," and "oh, I know that, too," etc. Ideally that might be true, but I recommend the following test: imagine that you are sitting next to the dumbest student in the world, and that it is your job to explain to the student every detail of the logic. Go over in your head exactly what you would tell this student.
If you fully understand how to do the problems on the two problem sets, you will be in great shape for the exam Tuesday night.
Best wishes,
— Alan Guth —

MON 09/21/2015: Tutoring sessions
Dear 8.01L Students,
Our tutoring signup system is now in place at https://801l_tutoring.youcanbook.me/, thanks to Lina Necib. Initially Alberto Hernandez will be holding tutoring sessions on Tuesday, Wednesday, and Thursday at 4:00 pm, and Lina Necib will have tutoring sessions on Thursday at 3:00 pm, and Friday at 2:00 pm and 3:00 pm. All tutoring sessions will be one hour long, or more realistically 50 minutes, starting 5 minutes after the hour and ending 5 minutes before. Each tutoring session will be limited to three students. The sessions will take place in Room 8-320.
You can sign up by clicking on the desired hour, and then it will ask for your name and email address, and give you a place to enter a note if you want. You will be sent an email confirming your appointment, and giving you a link to use to cancel if you change your mind.
If you have trouble with the website, please email Lina Necib, lnecib@mit.edu. If you want tutoring but cannot find an existing slot that meets your schedule, you should also email Lina Necib, and let her know when you are available. We will try to accommodate you if we can. You should also remember that I and each of the recitation instructors have office hours. Mine is on Mondays 4:30-5:30 pm in Room 6-322, Prof. Milner's is on Wednesdays 4-5 pm in Room 26-411, Prof. Chen's is on Thursdays 3:30-4:30 pm in Room 24-504, and Prof. Jarillo-Herrero's is on Thursdays 3-4 pm in Room 13-2017.
Additionally, homework help and additional tutoring is available through the Tutorial Services Room (http://ome.mit.edu/programs-services/ome-tutorial-services-room), which is run by the Office of Minority Education (though all students are welcome to attend). You can request an appointment at this website: http://ome.mit.edu/programs-services/request-appointment.
Best wishes,
— Alan Guth —

WED 09/16/2015: Tutoring, and a few Problem Set 1 clarifications
Dear 8.01L Students,
First, let me announce that tutoring will start tomorrow. From 3:00 to 4:00 pm, Lina Necib will be tutoring in Room 8-320. From 4:00 to 5:00 pm, Alberto Hernandez will be tutoring in the same room. Tutoring differs from office hours in that you must sign up in advance. That we can assure that at most 3 students will be part of any tutoring session. In the future we expect to have a web signup system, but for tomorrow we will resort to old-fashioned email. If you want to participate in Lina's session at 3:00 pm, email her at lina.necib@gmail.com. If you want to participate in Alberto's session at 4:00 pm, write to him at a_h@mit.edu.
I also wanted to add clarifications to two problems on the Problem Set. On Problem 1-6, it says "calculate the ratio of the time he is above y_max/2 to the time it takes him to go from the floor to that height." Here, "that height" refers to y_max/2.
In Problem 1-2(c), you are asked to calculate the average velocity, averaged "over time" and "over distance". In this case there are only two velocities that occur during the 100 meter run. To average "over time" is to compute a weighted average of the two velocities, weighting them proportionally to the amount of time the runner spends at each velocity. To average "over distance" is also to compute a weighted average, in this case weighting each velocity proportionally to the amount of distance over which the athlete ran at that velocity.
Best wishes,
— Alan Guth —

MON 09/14/2015: Min Chen's office hour
Dear 8.01L Students,
Prof. Min Chen's weekly office hour will be on Thursdays, from 3:30 to 4:30 pm, in his office, 24-504.
— Alan Guth —

MON 09/14/2015: My office hour
Dear 8.01L Students,
We decided in lecture today that my office hour will be on Mondays, from 4:30 - 5:30 pm, in my office, 6-322.
Should we start today? Why not? If you would like to talk with me, please come by between 4:30 and 5:30.
— Alan Guth —

SUN 09/13/2015: Pablo Jarillo-Herrero office hour
Dear 8.01L Students,
Hi all,
My office hours will be Thursdays 3-4pm, right after my 2pm recitation. It'll take me a few minutes to walk back from Stata to my office (13-2017), but I'll try to be there by 3:05pm at the latest. All students (not just R05 and R06 sections) are welcome.
Due to a conference I'm attending, I will not have office hours this Thursday Sep 17 (Prof. Milner will teach my recitations). Hopefully see many of you the following one. Feel free to email me though and I'll try to reply on the breaks.
Best regards,
Pablo

SUN 09/13/2015: Richard Milner office hour
Dear 8.01L Students,
Weekly office hour on Wednesday at 4 PM in 26-411
— Richard Milner —

SUN 09/13/2015: Recommended problems and lecture slides are posted
Dear 8.01L Students,
There are two additions to our website, http://web.mit.edu/8.01L/www: the lecture slides from last Wed and Fri, and also the first set of Recommended Problems.
The purpose of these recommended problems is described in its prologue:

  These recommended problems are a new and essentially experimental component of the course, to replace the use of Mastering Physics in previous years. They are likely to evolve as the course progresses, so your feedback will be particularly relevant here. The goal is to give you access to problems with instant feedback, mostly problems from the MITx 8.01 website. There will also be recommended problems from the Busza/Cartwright/Guth Study Guide, where at least the answers and in some cases fully worked solutions will be available. The problems are entirely optional, and will have no effect on your grades. We are in fact not keeping any record of your work on the 8.01 website.
  The due dates that you will see on the 8.01 website are intended for the 8.01 class, and will NOT be relevant to us. Since our schedule is more leisurely than that of 8.01, the problems that we will be doing on the 8.01 website will often be in ``post-due-date'' mode, which means that answers will be readily available. It is highly recommended, however, that you try the problems before looking at the answers.
  The current plan is to use these problems as a first look at the topic that we are about to start, with relatively easy exercises that allow you to make sure that you have mastered the basics. The weekly problem sets will be at the opposite end of the learning cycle, challenging you with problems that help develop a full understanding and a strong skill at inventive problem-solving. Thus, Problem Set 1 focuses on motion in one dimension, a topic which I hope to finish in lecture on Mon 9/14/15 or Wed 9/16/15. These recommended problems focus on vectors and motion in two or three dimensions, a topic that we will probably begin in lecture on Wed 9/16/15.
I hope that many of you will find this useful.
See you tomorrow in lecture,
— Alan Guth —

SAT 09/12/2015: Class Contact List is posted
Dear 8.01L Students,
The class contact list is now available, linked to the course web page at http://web.mit.edu/8.01L/www. It should be accessible to all registered students and listeners, and to course staff. Access requires an MIT certificate to identify yourself.
For those of you who are not already on the list, I strongly encourage you to join. Don't be bashful! I will paste below a copy of the email with the instructions for joining.
For those of you who are on the list, please let me know if you would like to make any changes to your entry. Any time during the term, if you would like to make changes, just send me an email.
And if you have any trouble accessing the site, send me email about that, too.
Best wishes,
— Alan Guth —

FRI 09/11/2015: Joining the MITx 8.01 website
Dear 8.01L Students,
As I mentioned in lecture and posted on the website, this year we will not be using Mastering Physics, but instead I will be posting a list each week of recommended problems for you to look at, which will mostly (and maybe entirely) come from the MITx website for 8.01. Your interaction with the 8.01 website will not be recorded, so it will not count in any way towards your grade in 8.01L. I think that most of you will find, however, that the instant feedback of online problems can be very helpful in your learning.
You will soon receive an email from the website, signed by Saif Rayyan, inviting you to join the site. From what I gather, you will be instructed to go to the following website to register:
https://lms.mitx.mit.edu/courses/MITx/8.01r_2/2015_Fall/about
The registration will only be open for about a week, so don't delay. You will need a browser that has MIT certificates installed (to test if that is the case you can go to http://web.mit.edu/certificates/test/).
If you have any problems accessing the site, you can email Saif Rayyan directly at srayyan@mit.edu.
I hope you find this useful. I will have the first list of recommended problems posted sometime this weekend.
— Alan Guth —

THURS 09/10/2015: Class Contact List
Dear 8.01L Students,
As I mentioned briefly in class, I would like to set up a class contact list. Classes are more fun and productive when students know each other and work together. To make it easier for this to happen, I have found it useful to set up a class contact list on the web. The goal is simply to make it easier for you to find each other. This could lead to regular meetings to work on problem sets in groups, or maybe just to occasional conversations. Don't feel that you have to be interested in a study group to sign up. If you want other students to know who you are, that's reason enough. If you are interested, please enter the information that you would like posted on the form below, and email it back to me. The web page will be visible only to other students in the class. Participation is completely voluntary, so you can skip this if you want, but I would encourage you to put yourself on the contact list.
There is a place for comments, which may seem a bit vague. You can put whatever you want, including nothing at all. You might indicate if you are looking for a study group. You might be inspired by some samples from the past:

  "I start psets early, available most evenings from 4pm, also 1 to 2:30pm on T,Th. Like ice cream."
  "I'd like to start problem sets at least a little early. I live in Boston, but I have a car."
  "Usually like to do pset for XXXX on sun or mon."
I might add that if you send something and then don't like the way it looks, you should feel free to send me corrections, or ask me to take it down altogether. I will act on your requests as quickly as I can.
Best wishes,
— Alan Guth —
*****************************************************************************************************************************
QUESTIONNAIRE:
Name:
Email:
Phone (leave blank if you never answer it):
Living Group:
Comments:
Do you have any objections to my posting your photo with the class contact list? Yes or No?
[If you send this form back but don't answer this question, I will assume you have no objection.]
*****************************************************************************************************************************
(If you give permission to post your photo, I have photos of almost all of you from the registrar. If you would prefer that I post a different photo, or if you are not officially registered, then feel free to attach a photo to your email. I can crop and rescale them, so anything will do.)

TUES 09/08/2015: Decision on Mastering Physics
Decision: We will not be using Mastering Physics this year, but instead we will post lists of recommended problems from the MITx 8.01 website, and possibly other sources. We will, however, set up a Mastering Physics class, so that any students who want to purchase access to it, for the extra problems or for online access to the textbook, will be able to do so.

FRI 09/04/2015: Uncertainty about Mastering Physics
Sorry, but things are still in a state of flux for 2015. We may or may not be using Mastering Physics. It should be settled in a day or two (i.e., by Saturday or Sunday, 9/6 or 9/7/15). In the meantime, we recommend that you not invest money in this product. If you have by any chance already purchased Mastering Physics, try to return it if you can. If you have invested money in Mastering Physics and cannot get it back, please let me (Alan Guth) know, and I'll see what I can do.