Online reading assignment: impulse and momentum

Physics 205A, fall semester 2015
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 previewing a presentation on impulse and momentum.


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.

"When you multiply the average force and the time of contact, you get the 'impulse' of the force."

"Linear momentum is the product of mass and velocity."

"How an impulse can affect the momentum of an object."

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.

"More applications."

"More on how linear momentum and impulse relate."

For the child hitting the tee ball with a bat, if the bat is swung such that it exerts the same net force on the tee ball for a longer time (by giving the bat more "follow-through"), the impulse on the tee ball will be __________, and the change in momentum of the tee ball will be:

less; less.	*** [3]
less; greater.	****** [6]
greater; less.	*************** [15]
greater; greater.	*************************** [37]
(Unsure/lost/guessing/help!)	******* [7]

Indicate which crash-test dummy (if any) has the greater magnitude quantity in the process of coming to a complete stop. (Only correct responses shown.)

Greater magnitude momentum change ∆p: (there is a tie). [31%]
Greater magnitude impulse "J" exerted on it: (there is a tie). [21%]
Longer stopping time ∆t: seatbelt and airbag. [35%]
Greater magnitude net (stopping) force ΣF: no seatbelt/airbag. [21%]

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

"So we will never lose any points if we fill in the other boxes but leave this one blank?" (Correct. You only need to fill something substantive in this last comment box if you leave the ones above it blank.)

"Thank you for giving an example before having us solve the problems on the worksheet last lecture--I would encourage doing that more!"

"Could you lecture more on the material you want us to read? And be more detailed on your explanations in class? Thank you."  

"I read the material and really tried to understand this, but i'm still pretty lost."

"How is the momentum affected by the atomic/molecular mass of different gases? Would it depend on the density or the pressure?" (That sounds dangerously like chemistry to me.)

"Please pick a different marker color than red/orange to make color differences from the black dry erase marker. Even with glasses on and sitting close to the front it's still impossible to read :(" (Okay, sure.)