TAM 251: Introductory Solid Mechanics

General Info

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


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


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.


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.


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

Computer-based Quizzes (PraireLearn)

Online Homework (PraireLearn)

In-class participation

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%



Prompt and regular attendance at, and participation in, lectures is required and will count towards your participation grade for the course.

Computer-based quizzes:

You will have 6 total online quizzes using the PrairieLearn system. You will not be allowed to use notes, textbooks, or electronic devices such as laptops (beyond the single computer necessary to take the online quiz) or cell phones. Solutions will not be posted. All quizzes will be administered through 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. Your lowest quiz score will be dropped.  

If you have an excused absence for the quiz, then you will take the assessment at a later date, or make other arrangements at the discretion of the instructor.

Online homeworks:

Weekly online homeworks will be assigned via PrairieLearn. Each assignment is due at 11:59 pm 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.).
  • 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:

TA office hours will be held online via Zoom.  

  Monday Tuesday Wednesday Thursday Friday
1011:50 am


Yaswanth Sai   Yaswanth Sai  
11:50 pm* Prof. Johnson

Prof. Johnson

Prof. Johnson Prof. Johnson  
3–4:50 pm Jaekwang Kim   Jaekwang Kim    

* Prof. Johnson will be on travel with effectively zero internet access from June 22–30.  During this time, the TAs will serve during his usual office hours.  

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 policy will help to 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 may see the professor and TAs 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.  

The use of Piazza should not replace the Zoom office hours, since some questions cannot be easily addressed via an online forum.

Final Exam:

The final exam will be a comprehensive, cumulative exam held in the CBTF with sign-ups available August 3 and 4 (these dates may be subject to change).