## 20150826

### Online reading assignment: motion

Physics 205A, fall semester 2015
Cuesta College, San Luis Obispo, CA

Students have a bi-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 the reading textbook chapters and previewing a flipped class presentation on (constant acceleration) motion.

Selected/edited responses are given below.

Describe what you understand from the assigned textbook reading or presentation preview. Your description (2-3 sentences) should specifically demonstrate your level of understanding.
"When we are talking about motion, there are three main components: postion, velocity, and acceleration. We can find the velocity by taking the derivative of position, and find acceleration by taking the derivative of velocity."

"I've have a solid understanding of calculus and algebra so all this is not a huge issue."

"I understand the graphical relations chart between kinematic quantities as well as the constant acceleration kinematic equations."

"I understand what we get when calculating the derivatives or the integrals of function graphs. I know that taking the chord slope results in the average rate of change, and the tangent slope at a point is the instantaneous rate of change at that point."

Describe what you found confusing from the assigned textbook reading or presentation preview. Your description (2-3 sentences) should specifically identify the concept(s) that you do not understand.
"I didn't find anything confusing because I've already seen all of this material before. It was good for review, however."

"I could use some clarification about calculating the velocity and acceleration using a graph. I thought that was a little confusing and could use some practice graphing actual examples step-by-step in class to get a more solid foundation for doing it myself."

"I'm just not that familiar with all the new symbols and abbreviations yet, and occasionally I have to re read them a few times and look back in the text to review before I can get new concepts."

"Just reading through the presentation did not help me understand the concepts, but it did help me key in on subjects within the textbook. But overall there was nothing that really confused me."

"I find how to use the chain of pain confusing. I also would like some examples of using the equations given to us on the presentation preview and how to know when to use which."

Mark the level of your exposure to (basic calculus) concepts of derivatives/integrals.
 None at all. * [1] Slight. ********** [10] Some. ************** [14] A fair amount. *************************** [27] A lot. ************ [12]

Mark the level of your expertise in algebraically solving multiple equations for multiple unknowns.
 None at all. ************ [12] Slight. **************** [16] Some. **************** [16] A fair amount. *********** [11] A lot. ********* [9]

Briefly describe the difference(s) between a chord slope and a tangent slope on a graph.
"A chord slope connects to two places on the graph. A tangent slope touches only one point on the graph."

"The slope of a (position versus time graph) chord gives average velocity over a shorter a time interval. Slope of a (position versus time graph) tangent gives instantaneous velocity."

"Not sure, I couldn't find the answer in the presentation and I have still not received my textbook."

Indicate how each of these quantities are determined from kinematic graphs.
(Only correct responses shown.)
Displacement ∆x: area under a vx(t) graph. [48%]
Position x: (None of these choices.) [50%]
Change in (instantaneous) velocity ∆vx: area under an ax(t) graph. [44%]
(Instantaneous) velocity vx: tangent slope of an x(t) graph. [61%]
Average velocity vx,av: chord slope of an x(t) graph. [50%]
(Instantaneous) acceleration ax: tangent slope of a vx(t) graph. [55%]
Average acceleration ax,av: chord slope of a vx(t) graph. [55%]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I'm really not digging this way of teaching. I had to deal with the same issue in another class last year--we basically had to teach ourselves and that was the worst way to learn for those who have never seen this material. Are we supposed to just read this material for the first time and understand it, just like that? We need more lecture on what we're supposed to get out of this class." (We always will have some lecture in class, as long as there is sufficient feedback to determine specifically what the class as a whole is having the most problems with. I can't lecture on everything everyone will ever need to know, as (a) there really isn't enough time for that in class, and (b) not everyone will have the same difficulties on every topic. So don't think you're being forced to teach yourselves--think of it as assessing what you are having the most difficulty with (well, sometimes it can be everything) such that we can best address these difficulties in class.)

"I'm not entirely sure how to read the chain of pain or necessarily how to use it. And what is a helpful way to determine which kinematic equation to use? Can you go over those in class?" (Yes, we'll go through those things in class. ALL THE THINGS.)

"Wow am I confused! I've been looking over this information the last couple days and nothing seems to be making sense to me."

"I needed a review on this and then I got it, no problem."