## 20140924

### Online reading assignment: uniform circular motion

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 uniform circular 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.
"Uniform circular motion will have velocity tangent to its circular path, and acceleration perpendicular to it, toward the center of the circle."

"How Newton's second law relates net force to circular motion. Even if the speed is constant, the direction is always changing."

"Nothing at all."

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 mathematical reasoning behind non-uniform circular motion is overly confusing. I find it difficult to translate this information into words."

"How to determine the direction of the net force for an object moving in a circle."

"While I understand most of the concepts, I don't get how to draw a free-body diagram for circular motion. And I don't understand what kind of questions you would ask about it."

For the "drifting" car (skidding around a circular track at constant speed), Newton's __________ law applies to its motion, and the forces acting on it add up to a net force that:
 first; is zero. * [1] second; points to the left. ************************** [26] second; points to the right. ************************** [26] (Unsure/lost/guessing/help!) ***** [5]

At the moment when the woman is at the bottom of her swinging trajectory (when the rope is vertical), Newton's __________ law applies to her motion, and the forces acting on her add up to a net force that:
 first; is zero. ************** [14] second; points upwards. ************************* [25] second; points downwards. ************* [13] (Unsure/lost/guessing/help!) ****** [6]

At the moment when the motor scooter is on the left side of the screen (traveling out at you), Newton's __________ law applies to its motion, and the forces acting on it add up to a net force that:
 first; is zero. ***** [5] second; points to the left. ********************** [23] second; points to the right. ************************* [25] (Unsure/lost/guessing/help!) ****** [6]

At the moment when the car is at the very top of the loop-the-loop, Newton's __________ law applies to its motion, and the forces acting on it add up to a net force that:
 first; is zero. ************* [13] second; points upwards. ************* [13] second; points downwards. ************************** [26] (Unsure/lost/guessing/help!) ****** [26]

At the moment when a person is at the right edge of the screen (traveling out at you), Newton's __________ law applies to his/her motion, and the forces acting on him/her add up to a net force that:
 first; is zero. ****** [6] second; points to the left. ******************** [20] second; points to the right. ******************** [20] (Unsure/lost/guessing/help!) ************ [12]

At the moment when the car is at the very top of its mid-air trajectory, Newton's __________ law applies to its motion, and the forces acting on it add up to a net force that:
 first; is zero. *************** [15] second; points upwards. ******** [8] second; points downwards. *************************** [27] (Unsure/lost/guessing/help!) ******** [8]

At the moment when the skateboarder is at the very top of his mid-air trajectory, Newton's __________ law applies to his motion, and the forces acting on him add up to a net force that:
 first; is zero. ************* [13] second; points upwards. ********** [10] second; points downwards. *************************** [27] (Unsure/lost/guessing/help!) ******** [8]

Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I'm good on this section."