# 141 Fall 2019 Week 10

Wow, last week of classes. We will review material while exploring new questions. Additionally, we will add trigonometry and you will be allowed to use the two kinematic formulas that most classes introduce in the first week of classes, now that you are able to solve questions without these formulas.

FINAL EXAM: Information is posted under Exam Week at the end of the timeline table on main class website.

Monday Shoot Monkey out of Tree

Before Class

• Hopefully, you’ve sent me the  url of your video. I’ve graded all the videos sent to me and responded to the person who sent me the link. If you have received no response from me then somehow I didn’t get the link. If this is the case, please send me the link again or talk to me in class. If you haven’t sent a link yet, please do it today.
• Please see: Big Picture Rotation Video that includes precession. It was assigned a few weeks ago. It is a good thing to see again, now that we’ve covered angular momentum as a vector.
• PS#11 is posted, due this Thursday.
• Solutions to PS#9 posted.
• Please consider shooting a monkey out of a tree… but also warm up by solving, Exercise 6, in section 7.6. I’ve added it to your problem set #11.
• See video on Fuzzy Dice
• Watch this video: Spinning Skater What are the forces on a skater’s arms when she is spinning very fast?
• Please see some old problems Solving flywheel with hanging mass This video is from winter quarter, 2016 so the problem number is different.
• We calculated the coefficient of friction between the calculator and the metal wheel two different ways please try to calculate the coefficient of friction each way…. I get numbers that differ by a factor of 2, but we can talk about it in class. Please do your calculations:
1. We tipped the wheel to a steeper angle until the calculator slid. The angle that the calculator slid at was when the opposite side was 79 cm and the hypotenuse was 1 m. Find theta (the angle that the wheel made with the surface of the table) and the coefficient of friction.
2. The table was 108 cm high, the radius was 18 cm, and the horizontal distance was 90 cm. When it fell onto the table, it fell 17 cm and moved a distance of 42 cm. For each of these measurements, find the speed of the calculator as it left the wheel, and the associated coefficient of friction.

In Class:

• Hand in PS#10
• Shooting Monkey out of tree!

After Class
This week, you will be asked to fill out two surveys/evaluations for this class. One comes to you via Email (I think) from the university.
The other I have made to help me better understand your experience in the class and better serve future students.

Tuesday: Last assessment 🙁

• Solving the Ladder Problem, this is from winter quarter 2016, so the number of the problem is different
• You saw my countersteering video last week, no? Do you understand countersteering? Now, please do a internet search for countersteering videos and watch one (or two if you like), don’t just take the first two that come up on the Google Search because we want the class to sample a large number of videos. There are many many countersteering videos. Many of them are much higher quality that the one I made. However, I’ve yet to see one that is actually correct. OMG, the crimes against humanity? Horrifying! So please watch them with a critical, critical eye. If you think everything on the video is correct, please send me the .url. If you find something wrong in the video, write it down for discussion with your people in class. If you like, leave a comment on the video explaining the problem with the video and/or post the url for my video: https://www.youtube.com/watch?v=mS5glFH2zJg& .
• Please fill out this course survey I made to help me understand your experience in the class. Please do the survey, and I’ll bring cookies to the final exam!
• Please fill out the university’s student evaluations that were Emailed to you.
• Assessment #9 solutions are posted on main class website.
• Solutions to PS#10 posted on main class website

In Class
Project #1: Make sure you have an “A”, or that you are satisfied with your present grade.

Wednesday:
Bring your bike to class day!!
first hour
Before Class

• Questions about the Final Exam?: Please see the final exam clarification document I posted on the main class website (just above the weekly time table document.
• Surveys: Please take the university survey for this class. The link was sent to you via Email.
• Please do short survey #10
• If you haven’t already, please fill out this course survey I made to help me understand your experience in the class. Please do the survey, and I’ll bring cookies to the final exam!
• Please fill out the university’s student evaluations that were Emailed to you.
• Please see: Bicycle Transmission, be prepared to answer the question, “why does a bike (or a car) have different gears?”
• See video from past students: Toy Car Catapult
• Assessment #9 solutions are posted on main class website.
• Solutions to PS#10 posted on main class website
• Office Hours for Friday have been changed to 9:00 AM. Because during our regularly-scheduled office hour, I’m going to take part in the climate strike… I’m taking part in a panel discussion from 12:45 – 1:45. Please come by and be a participant in the making of your world’s future.

In Class:

• Bring your bike to class! we explore bicycle transmission.
• Hand in your corrections for project #2. This could be in a form of a new video or a written document.

After Class

Thursday: Wow… our last class.
Before Class

• Questions about the Final Exam?: Please see the final exam clarification document I posted on the main class website (just above the weekly time table document.
• See video on solution for 2D inelastic collision from a problem set from years past.
• Spring Energy Conversion from a past midterm.
• If you haven’t already, please fill out this course survey I made to help me understand your experience in the class. Please do the survey, and I’ll bring cookies to the final exam!
• Solutions posted for Assessment #10 and PS#11 on main class website.
• please also fill out the university’s evaluations of this course. The last day to do this is tomorrow. Very few of you have filled out these evaluations. Please do!!
• I’ll post the class responses for both evaluations for you to read after grades are handed in, so please make sure your voice is heard. I value your input even if it’s criticism that’s hard to hear!
• Please consider which string breaks first when I pull downward on a string attached to the heavy ball hanging on another string.
• FINAL EXAM:
NOT In our classroom as indicated on the main class website
• Want a practice final exam? Sorry, I don’t have one for you. HOWEVER, before Fall 2018, our pedagogy covered two-dimensional motion BEFORE rotational motion. Thus, MT#2 for Spring 2016 and previous classes has a lot of the same kind of questions that you can expect from our most recent 3 weeks of material. You can access these classes from this website: http://sharedcurriculum.peteschwartz.net/