## 20120905

### Online reading assignment: free fall

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 free fall.

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.
"The acceleration of an object is always downward no despite whether the objects is moving up, down, or at rest."

"When an object is thrown up, the velocity of the object at the highest point is zero, but the acceleration is not zero."
Describe something you found confusing from the assigned textbook reading or presentation preview, and explain why this was personally confusing for you.
"Is drag always neglected when considering objects in free fall?"

"I found it difficult to say whether any of the examples in the presentation were actually free fall."

"I was wondering why at the highest point of an object being thrown upward the velocity is zero but the acceleration is not zero?"
Explain what assumptions are made about the amount of drag (air resistance) on an object said to be in free fall.
"That free fall is an idealization since there is always some air resistance."

"Air resistance is so minimal it is taken as non-existent."
Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I enjoyed the flash card time with the 'chain of pain.' It really helped me grasp the idea of how to use it."

"I like how the reading assignments are assigned before we talk about them in class. It gives me a heads up to what we will be discussing, and I can have questions ready if I'm confused about something in the reading."

"I need much more intensive time spent in class on example problems. I wish we could go over every homework problem from this last week."
(Come to posted office hours or make an appointment; ask questions just before/after lecture or via e-mail.)

"Will this class include trigonometric functions, cosine, sine, etc.?"
(Starting with the next chapter on vectors.)

"Would you include the air resistance if there was a large fan placed under an object in free fall?"
(Since drag is significant, the object cannot be said to be in free fall.)

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