## 20140825

### Online reading assignment: speed and velocity

Physics 205A, fall semester 2014
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 the reading textbook chapters and previewing a presentation on displacement, distance traveled, and average/instantaneous speed/velocity.

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.
"Displacement only applies to starting and ending positions. The average speed is always positive, distance traveled over time."

"Average speed is usually larger than the magnitude for average velocity."

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 don't fully understand how short the displacement must be for instantaneous velocity."

"It seems odd that displacement can be positive or negative."

"Average speed versus average velocity."

Briefly describe how you would walk along a straight, level road such that your distance traveled would be longer than your displacement.
"By walking in the opposite direction of where you plan on going, and then walking towards your destination, you will have walked further than your displacement."

In general, average speed will be __________ the magnitude of average velocity.
 less than. ********* [9] equal. ************* [13] greater. ******************** [20] (More than one of the above choices.) ****** [6] (None of the above choices.) ****** [6] (Unsure/guessing/lost/help!) ****** [6]

An odometer measures an object's:
 displacement. * [1] distance traveled. ******************************************************** [56] (instantaneous) velocity. ** [2] (instantaneous) speed. [0] (Unsure/guessing/lost/help!) * [1]

A speedometer measures an object's:
 displacement. [0] distance traveled. *** [3] (instantaneous) velocity. ********** [10] (instantaneous) speed. *********************************************** [47] (Unsure/guessing/lost/help!) [0]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"Go over, maybe with an example or graph, average speed versus average velocity."

"What is the difference between displacement and distance traveled?"

"Can you go over more stuff in class rather than give us problems to do?"

"If an object starts at a location then ends up back at the starting location afterwards, wouldn't that make the displacement zero?" (Yes.)

"I am feeling overwhelmed by the material in the class already. Where can I go to get help outside of class?" (According to the Student Success Center calendar, physics tutoring is scheduled Monday-Wednesday 2:00-6:00 PM in building 3300.)