TAM 251: Introductory Solid Mechanics

General Info

Grades Formal Assessment Contact Info
Website Grading Lectures Office hours
Course description Final grades i-Clickers Online forum
Prerequisites   Quizzes  
Reference text   Discussions  
    Online homework  
    Final exams  


Website: The official class website is http://courses.engr.illinois.edu/tam251/

Description: Relationship between internal stresses and deformations produced by external forces acting on deformable bodies, and design principles based on mechanics of solids: normal stresses, shear stresses, and deformations produced by tensile, compressive, torsional, and bending loading of members; beam deflections; elastic energy and impact; multi-dimensional stress states; buckling of columns.

Big Idea: Solid materials deform and break. The extrinsic relation of force and displacement is governed by intrinsic material measures of stress and strain. The challenge is to connect the extrinsic to the intrinsic.

Prerequisites: TAM 210 or TAM 211.

Reference texts:

There is no required textbook for this class. However, theses texts are very useful

  • R. C. Hibbeler, Mechanics of Materials, 9th edition, Pearson, Prentice Hall, 2014.
  • F. B. Beer, E. R. Johnston, J. T. DeWolf, and D. F. Mazurek, Mechanics of Materials, 7th edition, McGraw-Hill, 2015.
  • R. R. Craig, Mechanics of Materials, 3rd edition, John Wiley & Sons, 2011.

Grading: The total score for the course is computed with the following weights:

Computer-based Quizzes (PraireLearn)

Quiz Grade= max([First Try, 1/3*(First Try) + 2/3*(Quiz Retry)])

In-lecture Quizzes

Online Homework (PraireLearn)

Discussion worksheets

In-lecture iClickers

Final Exam









Final grades: The total score s corresponds to final grades as follows.

97% ≤ s < 100% A+ 93% ≤ s < 97%  A 90% ≤ s < 93%  A-
87% ≤ s < 90% B+ 83% ≤ s < 87%  B 80% ≤ s < 83%  B-
77% ≤ s < 80% C+ 73% ≤ s < 77%  C 70% ≤ s < 73%  C-
67% ≤ s < 70% D+ 60% ≤ s < 67%  D 55% ≤ s < 60%  D-
s < 55%


Lectures: Prompt and regular attendance at lectures is required to obtain credit for iClicker content.

iClickers: Short quizzes are conducted during lectures using iClickers (50% participation, 50% correctness). An iClicker remote can be purchased from any of the bookstores, and must be registered on Compass, under the tab "Register i>clicker". You need to register your iClicker by the end of Week 2, when the iClicker roster will be synced for the last time. The first iClicker use for credit will take place in Week 2 of the semester. Your lowest three scores will be dropped. These drop should be reserved for unexpected occurrences such as sickness or a family emergency.

In-lecture quizzes: You will have two 50-min quizzes during the semester (check the dates on the schedule page). Each quiz will have two free-response questions using the symbolic format often used during lecture. They are designed to assess your problem solving skills on course material.

Computer-based quizzes: You will have 7 total online quizzes using the PrairieLearn system. You will not be allowed to use notes, textbooks or electronic devices such as laptops or cell phones. Solutions will not be posted. All quizzes will be held in the Computer-Based Testing Facility (CBTF). Make sure to check the CBTF website to get information about the facility and what you need to do to sign-up for your quiz.

Discussion sections: Prompt and regular attendance at your discussion section is required. You must attend only the discussion section in which you are enrolled. You will not receive a grade for the worksheet if you attend the wrong discussion section.

The discussion section schedule is listed below.

  Monday Tuesday Thursday
9-10     ADC
Liz, Colton, Zixu
10-11     ADD
Liz, Colton, Haoyu
11-12     ADE
Liz, Colton, Haoyu
12-1 AD1
Anthony, Jeff, Shaoting
1-2 AD2
Anthony, Jeff, Jake
2-3 AD3
Matt, Shaoting, Jake
Rebecca, James, Jeff
3-4 AD4
Matt, Katie, Zixu
Rebecca, James, Zach
4-5 AD5
Matt, Katie, Haoyu
Rebecca, James, Zach


Online homeworks: Weekly online homeworks will be assigned via PrairieLearn. Each assignment is due at 11:59pm on the assigned due date. Due dates are available inside PrairieLearn. These assignments place an emphasis on mastery. The idea is to keep doing questions until you master the underlying concept or method. Once you do, you should be able to answer these questions very quickly.

The way this works in PrairieLearn is that each question has a value, a point total, and a point maximum. If you answer a question correctly, two things happen:

  • The point total increases by the value, until you reach the point maximum.
  • The value increases (2x, 3x, 4x, etc.).

If you answer a question incorrectly, one thing happens:

  • The value goes back to what it was originally (1x).

This system rewards repeated correct answers, which tend to demonstrate mastery. There is no penalty (other than resetting the value) for answering a question incorrectly, so don't be afraid to submit an answer. Similarly, don't be afraid to keep doing a question after you reach the point maximum - your point total with never go down!

If you click on the "?" just to the right of the line about available credit, you'll see all the dates associated with this homework. In particular, it says:

  • you can receive 100% until Main End Date
  • you can receive 80% until Extended End Date(two days later)
  • you can receive 0%, but can keep doing problems as practice for the rest of the semester.

Note that your score will never go down. For example, if you achieve 90% by the Main End Date, you won't be able to increase your score after that time, but you won't be penalized for not reaching 100% - your score will remain 90% forever. On the other hand, if you achieve only 70% by the Main End Date you will be able to increase your score after that time (to a maximum of 80%) until the Extended End Date.


Office hours:

Teaching and Course Assistants office hours are held in 429 Grainger, according to the schedule below. Office hours start in Week 2 of the semester.

  Monday Tuesday Wednesday Thursday Friday

Prof. Hu

(2138 MEL)


Dr. Johnson

(130 MechSE West*)


Dr. Johnson

(130 MechSE West*)




Dr. Johnson

(130 MechSE West*)

Matt, Colton
3-4     Rebecca  Anthony Matt, Colton
4-5   Anthony    Anthony, Jeff Matt, Haoyu
5-6   Anthony, Zixu James, Zixu Jeff  
6-7 Jake Katie, Shaoting James, Zixu Rebecca, Zach  
7-8 Jake Katie, Shaoting Zixu Rebecca, Zach  

* MechSE West is the Optical Physics Engineering Building


Online forum (Piazza): This class uses Piazza for ALL communications between the instructor, TAs, CAs, and students. Students should not communicate with instructors via email. This is so we can ensure a faster response and keep everyone informed about what's going on.

Students are encouraged to post public messages on Piazza ("Post to Entire Class"). If you like, you can post anonymously, but we encourage everyone to use their name because it makes a friendlier and more welcoming environment. We will never judge anyone for asking anything on Piazza, and you will see professors, TAs, and CAs making mistakes and saying stupid things as well!

You can use the private feature on Piazza by posting a message visible only to the Instructors. In this, you must type "Instructors", instead of sending a message to a specific TA or instructor. Again, this helps to ensure that you get a prompt response.

TAs and CAs are scheduled to be checking Piazza on the following days:

Sunday Monday Tuesday Wednesday Thursday Friday Saturday
Rebecca, Jake Matt, James Anthony, Jeff Liz, Zixu, Shaoting Zach, Colton Katie Haoyu

The use of Piazza should not replace the in-person Office Hours time, since some questions cannot be fully addressed via an online forum.

Final Exam: The final exams will be hand written and cumulative (covering all course material). They will be held in MSEB 100 not CBTF.

  • AL1: Thursday, May 10, 1:30-4:30pm
  • AL2: Wednesday, May 09, 7:00-10:00pm
  • Final Exam Conflict: The final exam is set to follow the non-combined final exam schedule. Therefore, we are not offering an official conflict final exam.

    If you believe you have a valid reason to request a conflict exam, please follow the steps below:

    • Check if you indeed have a VALID reason according to the student code.
    • Request your conflict final exam using Piazza (private message to Instructors).
    • In the summary line, write "Final exam conflict request"
    • Indicate clearly the reasons of your request and attach any relevant documents.