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 reading textbook chapters and reviewing 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.
"I am starting to understand the 'chain of pain' much more now, especially after the practice we had in lecture last week."
"Position-time graphs and velocity-time graphs are becoming easier to read and understand with the help of the 'chain of pain.' The more I look at the chain of pain and the graphs, that more they appear logic-based."
"I have a much better understanding of chord and tangent slopes. A chord slope touches two different points on a graph, and therefore represents an average; whereas a tangent slope only touches one point on the graph, providing instantaneous information."
"I understand the how and why of the 'chain of pain,' though I have yet to memorize it."
"We can solve one-dimensional motion problems using kinematic equations by determining the known and unknown variables and then selecting the appropriate equation(s) to solve for the unknowns. These equations only apply when acceleration is constant."
"There are four equations we need to know regarding time, velocity, acceleration, and position. We need to know three variables per equation in order to solve for the fourth introduced variable or else it isn't solvable."
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 am still confused about the 'chain of pain' chart. I am not sure what the arrows lead to and how to figure out how to solve a problem using it."
"After attending the class last Wednesday, the 'chain of pain' was not as confusing as it was earlier. The hardest part is just memorizing each process and how to get to each piece of the chart."
"The kinematic graphs are still confusing to me; I need to memorize the 'chain of pain' and how to find chord and tangent slope."
"The constant acceleration equations. I am unsure of when they are supposed to be used during certain equations."
"I am struggling with deciding which constant acceleration equation to use for these problems. It's difficult for me to confirm which quantities are given, especially with the UAV example."
"I am still a bit unsure of how to extract what the problem gives and then plug that information into the equations. I am also still a bit confused on picking the best kinematic equation. I know you pick based off of what information is given, but extracting the information proves to be a bit difficult for me."
"Not much at all. You just have to pay attention to what the problems are asking for."
Mark the level of your expertise in algebraically solving multiple equations for multiple unknowns.
None at all. * [1] Slight. * [1] Some. ************* [14] A fair amount. ********************** [22] A lot. ****** [6]
NRMA Motoring and Services
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"The braking distance for a 2012 Chrysler 300C to slow down from 31 m/s to a complete stop is 50.3 m. Assume that the acceleration is constant as the car slows down to a stop, and always points in the opposite direction as its velocity."
From the statement of this problem, determine whether the values of these kinematic quantities are known/given or are unknown/undetermined (without solving the problem numerically).
(Only correct responses shown.)
Final horizontal position x (initial horizontal position x0 assumed to be 0): known/given. [86%]
Initial horizontal velocity v0x: known/given. [89%]
Final horizontal velocity vx: known/given. [82%]
Horizontal acceleration ax: unknown/undetermined. [75%]
Final time t (initial time t0 assumed to be 0): unknown/undetermined. [75%]
For the Chrysler 300C, the horizontal distance traveled is __________ the magnitude of the horizontal displacement.
less than. ** [2] equal to. ******************************** [32] greater than. ******** [8] (Unsure/guessing/lost/help!) ** [2]
André Zehetbauer
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"Jamaican sprinter Usain Bolt holds the world record for the 100 m sprint, covering that (straight-line) distance in 9.58 s in Berlin, 2009. Assume that his acceleration starting from rest to when he crosses the finish line is constant, and always points in the same direction as its velocity."
From the statement of this problem, determine whether the values of these kinematic quantities are known/given or are unknown/undetermined (without solving the problem numerically).
(Only correct responses shown.)
Final horizontal position x (initial horizontal position x0 assumed to be 0): known/given. [95%]
Initial horizontal velocity v0x: known/given. [52%]
Final horizontal velocity vx: unknown/undetermined. [52%]
Horizontal acceleration ax: unknown/undetermined. [77%]
Final time t (initial time t0 assumed to be 0): known/given. [95%]
For Usain Bolt, the horizontal distance traveled is __________ the magnitude of the horizontal displacement.
less than. *** [3] equal to. **************************** [28] greater than. *********** [11] (Unsure/guessing/lost/help!) ** [2]
UAV Factory
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"A portable pneumatic catapult is able to launch a Penguin B unmanned aerial vehicle (UAV) from rest to a final speed of 23 m/s along a 4.0 m rail. Assume that the rail is horizontal, and that acceleration of the UAV starting from rest to when it is launched is constant, and always points in the same direction as its velocity."
From the statement of this problem, determine whether the values of these kinematic quantities are known/given or are unknown/undetermined (without solving the problem numerically).
(Only correct responses shown.)
Final horizontal position x (initial horizontal position x0 assumed to be 0): known/given. [61%]
Initial horizontal velocity v0x: known/given. [82%]
Final horizontal velocity vx: known/given. [89%]
Horizontal acceleration ax: unknown/undetermined. [61%]
Final time t (initial time t0 assumed to be 0): unknown/undetermined. [84%]
For the UAV, the horizontal distance traveled is __________ the magnitude of the horizontal displacement.
less than. **** [4] equal to. ************************ [24] greater than. ******** [8] (Unsure/guessing/lost/help!) ******** [8]
Ask the instructor an anonymous question, or make a comment. Selected questions/comments may be discussed in class.
"I am still a little unsure of the difference between horizontal distance and the magnitude of the horizontal displacement? I believe they are the same as long as the object is moving in one direction but not confident." (You are correct.)
"For the Usain Bolt 100-m sprint question, are we assuming that he's running on a straight or curved track? If it's curved, wouldn't that make the displacement magnitude smaller than the total distance traveled?" (If the sprint were along a curved track, then yes, the displacement magnitude smaller than the total distance traveled. However, a 100-m sprint is usually along a straight section of track, in which case the displacement magnitude would be equal to the total distance traveled.)
"When a problem says to assume acceleration is constant, does that mean it is 0?" (Not necessarily. When acceleration is zero, it is constant. But acceleration can be a constant non-zero value as well.)
"This is very basic stuff, but it is very important in order to do well in any type of physics."
"Can you please go over one of these questions including kinematic quantities in class." (We will.)
"Will Quiz 2 be structured in roughly the same way as the 'chain of pain' worksheet done in class last Wednesday?" (Yes, for several questions, the rest will be on kinematic equations and on free fall, which we will cover this week.)
"What is the best way to study for your tests?" (Study questions from old quizzes and midterms. Which is every example done in class, the majority of homework problems, and also the practice quizzes from last semester.)
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