5/18/09: Final
grades are now in Banner. We know that all
(well, nearly all) of you have worked extremely hard on
this course and are very proud of what you've been able
to do. The performance of the whole class
was exceptional, and it's been a pleasure and privilege
working with all of you. Some of you may be
pleasantly surprised by your grade; a few be
disappointed. But a B or even a C in a challenging
course is something to be proud of, and in the long run
people are going to be more impressed by what you can do
than by your grades in freshman courses.
We hope you enjoy your summer and look forward to seeing
you back next Fall. We will be looking for graders
and Lab TAs next December, so if you would like to make
your successors suffer as much as you have, contact us
at the appropriate time.
5/18/09:
Good job on a challenging final exam. If anyone is
curious, the solutions are
here.
The average was 62.5, and the
grade distribution is shown below. We are sorry to
inflict such a tough exam on you - the standard of the
class is very high and we needed to make sure that the
exam scores were not determined only by small algebra
errors.
5/13/09: You
may bring two double sided 11x8.5 sheets of hand
written reference notes (which must be legible without
resorting to optical, electron or scanning probe
microscopy) to the exam.
5/7/09:
ROOM CHANGES FOR FINAL EXAM: In a belated
attempt to prevent spread of swine flu, the University
has decreed that students must sit at least 3 feet apart
during final exams. Since most of you have been
packing yourselves into the last 3 rows of B&H166 for
lectures throughout the semester it is likely that you
have already caught most known diseases and have
probably created several new ones; nevertheless, here
are the new locations for the EN40 final:
ENGN 0040 S01 2:00 PM, May 15,
2009 Barus & Holley 158
ENGN 0040 S02 2:00 PM, May 15, 2009 Barus &
Holley 166
ENGN 0040 S03 2:00 PM, May 15, 2009 Barus &
Holley 166
ENGN 0040 S04 2:00 PM, May 15, 2009 Barus &
Holley 168
ENGN 0040 S05 2:00 PM, May 15, 2009 Barus &
Holley 141
5/6/09:
Prof. Bower will be offering EN4 help, recitations of
Scyld Scefing's funeral scene from 'Beowulf', Hungarian
conversation, performances of light chamber music, and
back-rubs between 10am and 4pm Mon May 11-Thurs
May 14. These will either be held in room 731 or
room 096, depending on the level of demand.
5/6/09:
Evening TA office hrs will not be held the week of May
4-8, but will be held as normally scheduled between May
11 and May 14 to help with exam preparation.
5/6/09:
Some old final exams are now posted on the
Exams page
5/6/09:
Prof. Curtin will be available to answer questions on
any and all EN 4 topics during the entire day of Thurs.
5/14 (until
4pm due to a new schedule conflict). He will also have office hours 3-5 on Monday
5/11.
5/1: SOLAR
PANELS ARE NOT TO BE REMOVED FROM PRINCE LAB - if you
took a set away, please return them ASAP!!!
Others need to use them as well....
4/28: Solar car
calculations - there seems to be something inconsistent
in the data supplied by the manufacturer for the motor.
(possibly the stall torque was measured at a voltage
other than the nominal 3V). To fix this,
take T_0 = tau_0 = 0; beta = 0.00179Vs/radian and R=0.75
Ohms in the motor equations.
4/27: Anonymous
Homework - Ms. Gesualdi has several graded HW which have
no names on them. If you did not get a h/w
returned to you, this may be the reason! You
can claim your h/w by contacting her (and convincing her
that the h/w is really yours!)
4/27: ABSENCES
FROM FINAL EXAMINATION: The official rules regarding
absences from final examinations are posted on
http://www.brown.edu/Administration/Dean_of_the_College/faculty/exam_excuses.php
Faculty are not
permitted to grant final exam excuses or reschedule the
final. If you are seeking an excuse from the final
exam for any reason (e.g. FSAE car contest) please email
Professor Bower as soon as possible, who will contact
the Deans on your behalf. You may also need to speak
with the Deans separately. The makeup exam will be held
next semester.
4/27: Prof
Bower will hold office hrs in room 096 from 10:30-1:30
and 3:30-4:30 on Tues April 28.
4/22: HW #10 is
now posted, and due next Wednesday, April 29, at 5:00pm.
4/22:
Regular TA office hrs will not be held Wed or Thurs this
week
4/22:
Solar car project description is posted
here.
4/21: HW
#9 is due tomorrow at 5pm, at the usual place.
4/21: Prof. Curtin's office
hours will be held on Wed. 3:30-5:30 instead of
Thursday.
4/20: Prof Bower's office hrs
this week will be held on TUESDAY 10:30-12:30 room 096
instead of Thurs.
4/17: A short
HW #9 is now posted and will be due on WEDNESDAY, APRIL 22. A final
short HW #10 will then be due on WEDNESDAY, APRIL 29
4/15: There
seems to be some confusion about the last HW. That
HW was an INDIVIDUAL HW, not a group project. This
was stated clearly at the beginning of the Project
Description. Students who submitted a group
solution must re-submit an individual solution to
receive credit. This solution must not be a copy
of the prior submission nor a copy of the now-posted
solution. Students are reminded that they are
bound by the honor code in this regard.
4/13/2009:
No recitations this week - but Profs will be in Prince
Lab to oversee construction. No lecture on
Tuesday. Lecture on Thursday, however. See
you in Prince Lab.
TAs will oversee construction from 2-6 Monday-Thursday.
Sign-up for testing times on the sheet posted in Prince
Lab.
4/10/2009: The
solution to the Pendulum analysis may be found
here. The "final answer" is at the end of the
file. Good luck with your designs.
4/9/2009: A MATLAB code that simulates the
full 3D motion of the trifilial pendulum can be
downloaded
here
Given values for the pendulum geometry and test object,
the code compares the value of I_object that you measure
using the pendulum (using the measured period and
formula derived in HW) with the actual value. (The two
don't agree exactly because your formula is
approximate). It also animates the motion of the
pendulum.
You can use the code to test the effects of making the
rotation angle of the pendulum too large, making the
pendulum swing sideways, or accidentally introducing a
misalignment between the COM of the test object and the
center of the platform.
4/9/2009: The Women in Science and Engineering
program will be holding a "speed meeting" event next
Monday (4/13) for first-year students to meet faculty
members who might be interested in serving as their
sophomore advisor. We will be in Petteruti Lounge from
5:30 to 7 pm.
4/9/2009:
Prof. Curtin will have office hours 2:30-3:30 on
Thursday.
4/4/2009:
The Vibrations/Rigid-Body Design Project is now posted
under the Projects section. Slight
clarifications added on 4/6/09.
4/4/2009:
HW #8 is now posted and due Friday April 10. It
consists of the analysis phase of the
Vibrations/Rigid-Body Project. The HW is Part 2 of
the Project Description.
4/2/2009: In
case you forgot, the relationship between exponentials
and sines/cosines is:
exp(i w t) = cos(wt) + i sin(wt) where i =srt(-1)
and w is the frequency.
4/1/2009:
Note that last Monday a small correction was made to the
last HW Prob, referring to an example problem found in
the on-line notes (rather than being in a previous HW).
3/26/2009: Check our Java
program to
visualize forced vibrations
3/26/2009: Some lunar
project animations are posted
here Not all may
download successfully, and some files may be missing - if
so we apologize.
3/25/2009: HW
#7 is now posted...We know you have been waiting all
break to work on it.
3/18/2009:
For the HW Prob. 2, the general result does depend on Lo.
So, please solve using L=Lo.
3/17/2009: Great job on the lunar design project - the
remaining projects will be nowhere near as difficult as
this one, we promise. If you did an animation for the
project, please email your files to Professor Bower -
we'll web post them.
3/17/2009: Midterm grade distribution is shown below.
3/13/2009
HW 6 is now posted, due next Friday, March 20
3/11/2009: Due date for the satellite project has
been changed to TUESDAY next week
3/9/2009:
Class attendance is not required on Tues - but come to
class if you have questions on the lunar impact project.
If you have a laptop, bring it to class, as we will not be
able to accommodate the whole class in the instructional
facility.
3/6/2009:
Sections and class on Mon-Wed next week will be held in the
instructional computer facility - these will be help
sessions for the lunar impact project.
3/2/2009:
Prof. Bower will have office hours on WED afternoon 1:30-3:30 rather than on Thursday.
3/2/2009:
Prof. Curtin will have office hours on WED afternoon
3:30-5:30 rather than on Thursday.
3/2/2009:
Summary slides on the main topics covered in EN40 so far
can be downloaded
here (ppt)
3/2/2009: Exam
Information:
Date: Thursday March 5th, 9:00-10:20 (in class hrs)
If you are in S01 (Prof Curtin's section) take the exam in
room 751 B&H
All other sections take the exam in 166 B&H
Exam is CLOSED NOTES. You may bring 3 double sided
hand-written pages
of reference notes.
Calculators are permitted (but will not be very useful).
3/2/3009:
A few old exams have been posted on the
exams page. If you
can't do any of them DON'T PANIC - the course has been
changed and there is a lot of stuff on the old exams that
was not covered this year to give more time for design
projects and MATLAB.
3/2/2009:
Details of the
Lunar Impact
Project are posted
2/27/2009: The
web server is blocking files with a .m extension, so the
links for the MATLAB snooker code given in the HW dont
work. You can download the code
here (it's
renamed as a .txt file to fool the server, but save it as a
.m file)
2/13/2009: If
anyone is really lost with MATLAB and would find some
additional classes/tutoring sessions helpful we can arrange
some additional help on Mon or Tues next week.
Email prof Bower
if you are interested... Also feel free to use office
hrs or contact faculty/TAs to discuss design projects.
2/13/2009:
Faculty and TA office hours will run as normal next week
(even on Mon and Tues). TA office hours will be held in the
computer facility, and Faculty/TAs will be available in the
instructional facility during Section on Wednesday to help
with the project.
2/13/2009:
Design projects will be tested on Friday Feb 20.
Tests take about 15 mins. You can reserve a test time
by signing up on the sheet posted in the Petterutti Design
Lab (on the noticeboard just outside the 'engineers
love-shack' that was used as the EN3 workshop). Come
to your test time 10 mins early or so, to give you time to
assemble your design and set up for your presentations.
2/5/2009: If
you are feeling adventurous and want to meet other
beautiful, exciting engineers, email
Stephanie_Gesualdi@brown.edu to be assigned to a lab
group for the first design project. But if you just
want to work by yourself or with the same boring group you
always hang out with that's OK - in this case there is no
need to tell us who your lab group are.
2/5/2009: A
short description of the MAPLE dsolve function can be
downloaded here
2/4/2009:
Detailed requirements for the mass launcher project (due
Feb 20) are now posted <download
pdf >
2/3/2009: TA
office hours are in 096 this week.
1/26/2009: TA
office hours will be held in the Computing Instructional
facility this week
1/22/2009: A
small clarification was added to the MATLAB HW - your file
should be a function, so that
the nested functions will work - e.g.
function my_homework
Solutions to the
problems
Nested functions
for the ODEs
end
1/21/2009:
Reminder - logging into the instructional facility
Your
Username
Your username will be automatically generated from up to
the first six characters of your last name, followed by the
first character of your first name, followed by your middle
initial. Non-alphabetical characters such as hyphens and
apostrophes will be skipped. If your last name is less than
six characters long, your username will be shorter. For
example, for a student named Josiah S. Carberry, the
username would be “carberjs”.
Your
Password
Your initial password will be automatically generated from
your Banner ID. It will be the first letter of your last
name in uppercase, followed by your complete Banner ID with
a lowercase “b”. For example, for a student whose last name
is Carberry and Banner ID is B12345678, the initial
password would be “Cb12345678”. When you login for the
first time you will be prompted to create your own
password. The password that you choose must be at least
eight characters long, cannot contain your username, and
must contain at least three of the following four types of
characters: A-Z uppercase, a-z lowercase, 0-9 base-10
digits, and non-alphanumeric characters (e.g. !, @, #, $).
1/6/2009:
EN40 sections will meet as scheduled on Wednesday
January 21. Please go to the assigned rooms for
section, i.e.
Your section
instructors will introduce themselves and then take you
over to the instructional computer facility to start
working through the MATLAB tutorial.
1/6/2009:
Welcome to the 2009 EN40. We have made a number
of revisions to the course this year, including
introducing MATLAB to solve problems in dynamics; new
design projects; and changes to the course content.
We hope that
you will find the revised course interesting and
challenging. Changes always cause problems, however,
so please be prepared for glitches, and let us know
early how the course is going for you - don't wait
until end of semester evaluations!
