33-151 Matter and Interactions I Fall 2017

Professor: Kunal Ghosh
Wean Hall 7303
Phone: 412-268-3413 
Required Text: The Modern Mechanical Universe
by Curtis A. Meyer.
This textbook has been written by Curtis Meyer to support the Matter and Interactions course at Carnegie Mellon. It focuses on the atomic structure of matter and the interactions that matter undergoes. The text emphasizes that there are only a small number of fundamental principles that underlie the behavior of matter, and that using these powerful principles it is possible to construct models that can explain and predict a wide variety of physical phenomena. The text also weaves our current understanding of the universe into the mechanics and introduces the basics of scientific computing.

Students can order the textbook from the on-demand publisher, from the author's storefront, students can download chapter 1 of the textbook on the course blackboard site.

Goals and Motivations:

Physics 33-131, which includes classical mechanics and thermal physics, is the first course in a two-semester sequence of introductory calculus-based physics courses offered to science and computer science majors. This course deals with the nature of matter and its interactions. The variety of phenomena that we will be able to explain and understand is very wide, from the orbit of a planet to the cooling of a gas.

The main goal of this course is to have you engage in a process central to science: the attempt to model a broad range of physical phenomena using a small set of powerful fundamental principles.

The specific focus is on learning how to explain the nature of matter and its interactions in terms of a small set of physical laws that govern all mechanical interactions, and in terms of the atomic structure of matter.

While this course will use computer modeling to both solve and understand complex physical systems, this is not a programming course and no programming experience is required.

Superficially, this course and Physics I for Science Students, 33.111, look very similar. They both use the same textbook, and cover similar material. However, this course will cover both more material, and in more depth than in 33.111. More difficult problems will be covered, and the course will take more of your time. However, you will be rewarded by a deeper understanding of science.


After successful completion of this course, you will be able to apply basic principles of energy, momentum and angular momentum conservation to solve real-world problems on the microscopic, macroscopic and astrophysical size scales. You will be able to apply methods to check the correctness of your answers and understand the approximations used to achieve that answer and how they impact its validity. You will also be able to solve these problems using different techniques including computational, analytical and simple approximations.

Your success in achieving these outcomes will be measured via standard in-class exams and programing work described below.


It is assumed that you have a very strong high school background in physics, either an AP physics course, or a University level course. It is also assumed that you have a very solid high school mathematics background, and that at a bare minimum you are currently enrolled in Calculus. No programing experience is required, though familiarity in interacting with a computer is expected.

The math needed is a basic knowledge of derivatives, which can be obtained by studying calculus concurrently. It is also assumed that you are familiar with and able to use vectors. The textbook offers a brief overview of vectors in Chapter 1. Finally, we assume that you are familiar with the terminology and concepts from your high school physics course.

Course Schedule

See also the page giving week-by-week lists of Activities. All assignments and activities are posted there so that you can download them when needed.


For more details on grading, please see the 'Grades' web page. It gives break downs on letter grades and also describes in detail how you can drop your lowest exam score by doing the project.

Final Exam 30%
Project 15%
3 one-hour Exams 45%
Assignments 15%
Quizzes 5%
Attendance and Participation 5%
Grades are based on an absolute basis: A 88 - 100%, B 75 - 88%, C 60 - 75%, D 47 - 60% and R 0 - 47%. There is no grading on the curve (grade breaks via rank in class). However, the grade boundaries may be lowered if an exam turns out be more difficult than intended.

Exams and Quizzes:

At the beginning of most Friday lecture/discussions, there will be a written quiz. Get to class on time since no make-up quizzes will be given. These quizzes are based on class discussions and textbook study. Your lowest quiz score will be dropped, and if you miss a quiz, that quiz will be counted as your lowest one. The schedule of quizzes as well as a few samples can be found on the 'Exam Page'.

There will be three exams during the course and a cumulative final exam. For more details, see the 'Exam' page. The dates of the exams are given there. The date of the final exam will be announced by the University by the middle of the semester. A missed exam will count as a score of zero. If you are involved in University Activities that will take you away from campus, please contact one of the instructors so that we can arrange with your coach for you to take the test while on the road.


The project provides an opportunity for you to carry out a research projects using material that we have studied in the course. The project is detailed on the project page. The essential details are that students will work in teams to design and carry out a project that is agreed upon by the students and the professor. A number of in-class miles stones need to be met leading to a poster on the project that will be presented at a department-wide poster session at the end of the semester. Each student will also write a short report on the work that they did.

In-class Questions and Answers:

During most lecture/discussion classes you will be asked to think about and answer some illustrative problems. These problems are meant as on-the-spot checks of whether you and your classmates comprehend the material. In a large class such as ours, this method gives everyone a chance to participate. The questions will occasionally be collected at the end of class and be used to note of your attendance in class on a given day. The questions will generally be based on the content of the present or previous lecture. Apart from the questions posed by the instructor, you can anytime raise your hand to ask questions if what the instructor says is unclear to you.

Class Attendance:

Too many students do not realize how important it is to come to class, and giving credit for attendance is one way of emphasizing its importance. In a recent semester in an introductory physics course where lecture attendance was not required, roll was taken in two consecutive lectures. It was found that 87% of the A students came to both lectures, 75% of the B students, 54% of the C students, 33% of the D students and 10% of those who were failing. Very similar results have been obtained in Calculus I and in another introductory physics course. Regular class attendance keeps you well connected to the course, so that you know at all times what's going on, what are the most important points, etc....

The most common cause of missing classes is lack of sleep. If you find that you are getting to bed very late and are missing this class, you need to get help in setting priorities and managing your time, so that you can get adequate sleep and attend classes regularly.

Attendance and Participation will account for 5% of you final grade. You are allowed to miss two classes without affecting your grade. (Note: University events do not count toward the two classes, but you must notify one of the instructors in advance.)

How to use the Textbook

Textbook study assignments are ideally done before the associated class discussions, and most students find that they get more out of class if they read ahead in the textbook. The class covers the high points of the new material, and you are expected to go back over all of the assigned material in the textbook and work the exercises in detail, to help fix the new concepts in your mind. Class discussions will not cover all of the assigned material; it is essential that you study the textbook carefully.

It is important that you take the study assignments seriously, a day at a time. If you ignore the book until it is time to attack the assigned homework problems, you are likely to waste a lot of time floundering around, desperately searching for a nonexistent magic formula somewhere in the chapter that sort of matches the homework problem, and you will lose the opportunity to acquire a deep understanding of the material.

If on the other hand you devote a modest amount of daily time to working through the new sections of the book, you will be in a position to attack the homework problems efficiently, based on a clear understanding of the fundamental physics principles rather than your ability to plug numbers into secondary special--case formulas.

Homework Problems

Homework problems will be graded and will count toward the final course grade. Homework is due at the start of the specified class; it will receive half - credit if handed in by 5pm of the specified day; it will not be graded if handed in later without a valid excuse.

Important: Homework must be legible and clearly organized so that we can easily follow your reasoning, or it will be returned without being graded!

Computer Work

We will assign computer homework, some of which will be done in class, and some to be done outside class. These computer activities emphasize computer modeling of physical systems and are designed to deepen your understanding of the nature of the modeling process. Computer modeling is an important skill that is playing an increasingly critical role in all of the sciences. We will teach you the techniques you will need; no previous programming experience is assumed.

Computer programming is a powerful tool, but even the most skilled programmer sometimes gets waylaid by a computer problem that is very difficult to debug. For that reason we make the following rule:

If you have worked seriously for an hour trying without success to debug a malfunctioning computer program, STOP! Get help from an instructor or from another student before continuing. We do not want you to spend hours and hours struggling with computer problems. We will make adjustments of deadlines when we work with you. However, you have the responsibility to start on an assignment early enough to be able to get help if necessary. Don't wait until 2:00 am of the day the assignment is due!


Scientists and engineers normally work in groups, and social interactions are critical to their work. Most good ideas grow out of discussions with colleagues. In this course, we want you to work with others as much as possible. Study together, help your partners to get over confusions, ask each other questions, and critique each others' homework write-ups. Teach each other! You can learn a great deal by teaching. But do turn in your own write-ups: if we find you simply copying someone else's work, each person gets zero credit.

While collaboration is the rule in technical work, evaluations of individuals also play an important role in science and engineering. Exams and quizzes are to be done without help from others. Cheating will be heavily penalized in accord with university regulations.

In principle, late work will not be accepted. If you are sick, or have a University recognized activity, contact the instructor to make arrangements.

Work turned in late but before 5:00pm of the day that it is due will be graded but given only half credit. Work turned in outside of class needs to be turned at Professor Meyer's office, (Wean Hall 8414). Slide it under the door if no one is there.


You should ask lots of questions in class to clear up any initial confusion you might have about a topic. If you fall behind for any reason, please let us know as soon as possible. The sooner we know about these situations, the better we can help you make up work. We will do what we can to help you complete the course satisfactorily, but an incomplete grade cannot be given simply because you fell behind.

An optional Course Center will be available. Come to work with other students on physics problems, with an instructor present to whom you can direct questions. It will be held on Wednesday and Thursday evenings in the recitation classroom, Doherty Hall A325.

Take Care of Yourself:

Do your best to maintain a healthy lifestyle this semester by eating well, exercising, avoiding drugs and alcohol, getting enough sleep and taking some time to relax. This will help you achieve your goals and cope with stress. All of us benefit from support during times of struggle. You are not alone. There are many helpful resources available on campus and an important part of the college experience is learning how to ask for help. Asking for support sooner rather than later is often helpful. If you or anyone you know experiences any academic stress, difficult life events, or feelings like anxiety or depression, we strongly encourage you to seek support. Counseling and Psychological Services (CaPS) is here to help: call 412-268-2922 and visit their website. Consider reaching out to a friend, faculty or family member you trust for help getting connected to the support that can help.

Accomodations for Students with Disabilities:

If you have a disability and have an accommodations letter from the Disability Resources office, We encourage you to discuss your accommodations and needs with the course instructor as early in the semester as possible. We will work with you to ensure that accommodations are provided as appropriate. If you suspect that you may have a disability and would benefit from accommodations but are not yet registered with the Office of Disability Resources, we encourage you to contact them at

Last Update: 8-22-16 by C. A. Meyer