Physics 325
Classical Mechanics I

Prof. Gregory J. MacDougall

& Info
Discussion Homework Gradebook


  • NEW New video lectures have now been posted on the Phys 325 channel of You should be able to find them either by searching for the channel, or following the link below and then clicking on the Phys 325 box below the video for a list of other media in the channel. There are four new videos. The subject material is Variational Calculus: motivations, definitions and simple examples. This information will be needed for your homework, and will set up next week's lectures on Langrangian mechanics. Please view before next week, and let me know if there are any problems accessing the material.- GJM Friday, March 24, 2017

  • NEW I have recently posted a trial video lecture on some of the material related to HW8 (how to put energy equations in "normal form", and thus find effective mass). This is supplementary to our regular lectures, and videos on material from the syllabus for last week (calculus of variations) will be posted in the coming days.
    This and future videos can be accessed at on the channel entitled "Physics 325- Spring 2017". Sign in with your netid and search for the course name. You should also be able to access the current lecture by clicking here. Wednesday, March 22, 2017

  • HM#9 has now been posted. Do not fear if you don't immediately know how to do it! It is based on your readings of Chapter 6, but also on the cyber-lectures that I will be posted in the coming days. Friday, March 17, 2017

  • Reminder that today office hours will be held in Loomis 144. I will be there. -GJM Thursday, March 16, 2017

  • Change of plans for next week: Due to scheduling conflicts, lecture on Tuesday, March 14 is CANCELLED. Lectures will resume on Thursday, and homework will be posted and due on the usual schedule. I will prepare and post an online lecture over the break to cover what we have missed, and keep us on track with the class syllabus.- GJM Thursday, March 9, 2017

  • Due to travel by several of the teaching team next week, the staffing of Office Hours will be different from usual. Tuesday and Wednesday office hours, both, will be manned by your grader team, Shaolei Li, Xueda Wen & Dewen Zhong. Prof. MacDougall will be manning the office hours on Tursday, March 16. Office Hours will be held at the same time and location as usual, and homework will still be due March 17.. Thursday, March 9, 2017

  • Midterm 1 scores have now been uploaded to Gradebook. Average was 66%, with a standard deviation of 19%. A full solution set for the exam can be found on the Homework section of the class webpage. Friday, Feb. 24, 2017

  • As there is no homework due this Friday, office hours on Thursday have been CANCELLED. Instead the time will be used to grade your Midterm exams. Please note that there will be a Homework 6 posted on Friday, to be handed in on March 3. Wednesday, Feb. 22, 2017

  • As mentioned in class, I am uploading the general proof for the decomposition of kinetic energy into contributions OF and WITH RESPECT TO an arbitrary reference point (A). Long story short, this decomposition only works if either (1) (A) is stationary or (2) (A) is the Center of Mass position. You can find the full derivation here. Wednesday, Feb. 22, 2017

  • The formula sheets for Midterm #1 (and Midterm#2 and the Final) can now be found on the Homework page. This will be provided with the exam, as will the 1D and 3D calculus formulas. Monday, Feb. 20, 2017

  • Another small change to the rooms for Office Hours. Tuesday office hours will now be held in Loomis 276. Wednesday, Jan. 25, 2017

  • Useful formula sheets have now been added to the Homework section of the webpage. Tuesday, Jan. 24, 2017
  • Anything on these sheets do not have to be proved in this course. Take a minute to look through them to see what is there.

  • Due to room availability, the room and time of Thursday office hours have been changed. Friday, Jan. 20, 2017
  • Please check below for updated information.

  • Website is up!     Monday, Jan. 17, 2017
  • Please take a minute to read through the general course information on this page, which explains the course structure and policies on homework and grading. Also included is a link to the course syllabus, which provides a week-by-week breakdown of topics covered in this course and suggested reading. Specific information on office hours will be included in the coming days.

    General Information

    Course Description
    This course constitutes a core requirement for Physics majors or minors at the University of Illinois, and covers major topics from the field of classical mechanics. Topics covered include the kinematics and dynamics of classical systems, including a review of Newtonian kinematics and dynamics; three dimensional motion, variable mass, and conservation laws; damped and periodically driven oscillations; gravitational potential of extended objects and motion in rotating frames of reference; Lagrangian and Hamiltonian mechanics.

    • Prof. Gregory MacDougall, MRL 216  → gmacdoug @ with "325" in the subject line
           or call me at 300-0147
    For specific questions about homework grading, please simply email the entire grader email list, and the appropriate grader will respond.

    Loomis 151,   Tuesdays and Thursdays, 1:00 - 2:20 pm

    Loomis 143,   Monday evenings, one hour in the period 4:00-9:00pm. The exact time of your discussion will depend on the particular section for which you registered.

    Office hours Beginning the week of January, 23rd.
    Loomis 276,   Tuesdays, 5:00-7:00pm,   Billy Passias & Jahan Claes
    Loomis 222,   Wednesdays, 3:30-5:30pm,   Prof. MacDougall
    Loomis 158 (Loomis 144 on Feb 2 and March 16),   Thursdays, 5:00-8:00pm,   Shaolei Li, Xueda Wen & Dewen Zhong

    Course Text Books
  • "Classical Mechanics" by John R. Taylor
  • "Introduction to Classical Mechanics" by David Morin
    which is available online @ UIUC Library; off-campus access needs VPN in Tunnel All mode

  • Syllabus
    See here.



    Course Grade Breakdown
    Homework will be 25% of the total grade, discussion attendance 5%, and exams will count for 70%. Two mid-term exams are worth 15% each, and the final exam is 40%.

    Homework due dates and time
    Homework assignments will be posted each week on Friday, and are due at 1:00 pm on the following Friday. Your solutions are to be deposited in the course homework box that is located on the second floor of Loomis Lab, at the entrance to the overpass to the Materials Research Lab (MRL) on the north side. Assignments which are late, but handed in by Monday at 1pm will lose 15%. Another 15% will be lost (30% total) for assignments submitted by Tuesday at 1pm. No late assignments will be accepted after Tuesday at 1pm! For assignments due within a week of a midterm exam, no late assignments will be accepted.

    General Policy Regarding Grading
    Homework is considered essential to learning course material, and should be treated as training for future work rather than as a test of what you already know. You should start working on an assignment early, close to when it is posted on Friday. We encourage students to work together, and get help from the professor or TAs when they encounter difficulties. We will happily explain difficult concepts during office hours and check your work for errors. For this reason, scores on homework are typically high (~95%). Don't make the mistake of starting your homework the day before it is due! (You know better.)

    Partial credit will be given on homework and exams if and only if the work is coherent. A random scattering of thoughts will not be awarded points. Simple numerical errors will not be strongly punished, however students are expected to be careful about their work and will lose points for errors which give incorrect physical results. The steps to receiving partial credit are: (i) write your solution neatly and coherently using equations and words to describe what you are doing (ii) checking your answer for consistency e.g. are units correct, does the solution behave correctly in known limits? Write as though you are explaining the problem to somebody who doesn't already know the answer! Expect the exams to be challenging but to be curved accordingly.