## 20120920

### Online reading assignment: Newton's third law

Physics 205A, fall semester 2012
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

The following questions were asked on reading textbook chapters and previewing a presentation on Newton's third law.

Selected/edited responses are given below.

Describe something you found interesting from the assigned textbook reading or presentation preview, and explain why this was personally interesting for you.
"How Newton's third law applies if both forces fulfill the three parts of POF-OST-ITO checklist."

"Once a system is defined all interactions can be classified as internal or external. You could define my house and the people and objects in it as an internal system, and then simply look at the rest of the forces externally."

"All interactions come in pairs."

"Newton's third law is extremely simple. :)"
Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"I found the rules of free body diagrams unclear."

"Being able to remember which of Newton's laws are which and when to use which one."

"Why is it that when two equal and opposite forces act on an object that why cannot be interaction partners?"
Consider two categories of motion. (1) Velocity that is constant and unchanging. (2) Velocity that is changing. Discuss whether or not there would be a third category of motion not already covered under these two categories.
"An object at rest."

"I can't think of a situation where there would be a third category. Maybe if velocity was non-existent, but the first category pretty much covers that."
Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Can you explain the interaction partners more in-depth please. Practice problems would really help to understand the Newton's third law." (The subsequent lecture will delve into Newton's third law with many flashcard questions and examples.)

"Do we turn in late lab assignments to you or to our lab instructor?" (All laboratory work (even if late) should be handed in person directly to your laboratory instructor, submitted via e-mail, or in placed in the Physical Sciences Division mailboxes in Building 2300, or as specifically required by your laboratory instructor's policies.)

"Do you allow make-ups on the quizzes?" (No, but your three lowest (or missed) quizzes are dropped.)

"Go over more examples and homework problems, please. I wish we could go over everything we've 'learned' already. I feel I need to start from scratch. : /" (With only so much time in lecture to address concerns as suggested by student responses to the online reading assignments and homework reports, if you require additional instruction/assistance, come to posted office hours or make an appointment; ask questions just before/after lecture or via e-mail.)

"Here's a comment to say I left a comment on your 'make a comment' spot."