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# 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:

**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. |

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." |

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.