## 20140903

### Online reading assignment: free fall

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 reading textbook chapters and previewing a presentation on free fall.

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.
"I understand the definition of free fall, and the acceleration, regardless of object mass. I also understand that no other forces act on an object other than the gravitational force."

"I understand the basic concepts and equations used in determining free fall of an object, whether it is dropped or thrown upwards."

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.
"The highest point of the object where the velocity is zero, but doesn't stay zero because it is still traveling and then the velocity increases. That for some reason is hard for me to see and could see myself getting easily confused with that."

"The equations are overwhelming and the graphs are confusing."

Explain what assumptions are made about the amount of drag (air resistance) on an object said to be in free fall.
"There is always some air resistance so it is said that free fall on Earth is an idealization, but since air resistance is so small it is assumed to be negligible."

"Air resistance is assumed to be negligible when measuring velocities of free-falling objects that aren't falling very fast."

For all possible cases of an object during free fall, ay =
 +9.80 m/s2. *************** [15] 0. [0] -9.80 m/s2. ************************************ [36] (More than one of the above choices.) *** [3] (Unsure/guessing/lost/help!) **** [4]

For all possible cases of an object during free fall, the distance traveled will be __________ to the magnitude of the displacement.
 less than. ****** [6] equal to. ************************* [25] greater than. *********** [11] (More than one of the above choices.) *********** [11] (Unsure/guessing/lost/help!) ***** [5]

For all possible cases of an object during free fall, the magnitude of the average acceleration will be __________ to the magnitude of the instantaneous acceleration.
 less than. ********* [9] equal to. ******************************* [31] greater than. ***** [5] (More than one of the above choices.) ***** [5] (Unsure/guessing/lost/help!) ******** [8]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.