141 Fall 2017 Week 4

Monday : Springs and Review
Before Class

  • I posted your feedback statements on the main class webpage
  • PS#4 due next Monday (before MT#1) is posted on main class website. Please have a look at it.
  • Hand in PS #3
  • See video about: Springs!
  • Potential Energy Graphs video
  • Some physical work I did at home
  • See Student Project Video: Measuring Speed of Bullet
  • Read 2.6 Springs
  • Read 2.7 Energy Graphs
  • Read 2.8, a review about the lens method, updated to include vectors
  • Solutions to PS#2 are posted. I posted three copies of good student work: one that is 10 pages, one that is 4 pages, and one that is 3 pages. See them on the main class website.

During Class

  • Discuss Problem Set #3 after handing it in.
  • a string breaks.



Before Class

  • Solutions for Big Exam! #2 posted on main class website.
  • See: Elastic Collisions with Walter Lewin at MIT
  • Read 3.0, Changing Reference frames and then, see the video below.
  • Elastic Collisions with Pete at Cal Poly by Changing Reference Frames This is my most popular video – after ~ 4 years, it has over 18,000 views. See if you can tell me why it’s the most popular of my videos.
  • Read 3.1, elastic collision in 1 dimension.
  • If you like, please check out 8.4 from the original OpenStax textbook to see how the rest of the world looks at elastic collisions in 1-Dimension using simultaneous equations. Please reflect on the following two questions
    • How do you compare this chapter to the chapters that I write?
    • How do you compare this method to the picture drawing method that I present in the video?
  • Important to consider for today’s class… your life may depend on it. You have two balls to throw against a door in order to close the door with the impact of the ball. One ball is perfectly elastic, and the other one is perfectly inelastic. Which ball will be most effective at closing the door? Why?
  • Optional reading on NPR about active learning in Physics Education Research. The author, Carl Weiman who won the Nobel Prize in Physics for Bose Einstein Condensation gave a talk at Cal Poly some 12 years ago calling on us to evaluate and innovate teaching with the same scientific process we use for other scientific research. Since then, he’s become prominent in Physics Education Research. He’s published a considerable amount about active learning strategies and over the years has become more outspoken about the futility of the lecture model and need to change.
  • Another NPR article about education:
    • “The first step is to teach Socratically, by asking questions and having students think out loud. This works much better than lecturing.”
    • “Teachers who find their kids’ ideas fascinating are just better teachers than teachers who find the subject matter fascinating,”

During Class

Elastic Collisions

Surviving a fire in your dorm room

Wednesday Friction!

Before Class

During Class

  • Big Exam #3


Thursday Review for Midterm.
Before Class

  • View Big Picture of Mechanics to get an overview of the first 4 weeks of mechanics.
  • Solutions for PS#2 sliding down a curved ramp question. I also go over some calculus that may be interesting here. This is from a past class, so the numbers are different.
  • Review how I solve the Ballistics Pendulum Video from an old problem set.
  • This is a slightly different version of the accelerating car, but try this video out if it helps you understand Powerful car accelerating I reference a question from the problem set but this is an old video and I didn’t assign this question this quarter. Thus is is all the more important that you learn from the video.
  • Study for Monday’s midterm!: Take MT#1 from Spring 2017 under test conditions: 50 min. Do the whole thing, It’s great to do it with your fiends, but pretend it’s an exam with no talking for the entire 50 minutes. Then you can compare answers afterwards.
  • After you finish the Practice MT#1 (above), please see my feedback to last year’s MT#1 that you just took. Then address the questions again to see if you can improve. You might do this as a group.
  • Someone in class lost a blue TI-84 calculator (great for a straight edge or finding coefficients of friction). If you found it, please let me know.

During Class

  • How fast can you throw a ball?
  • Prepare for MT#1

After Class

  • Make sure you see the review videos before next Monday (when we take MT#1).
  • If you want to do more questions to study for the midterm next week, you can access old classes on my sharedcurriculum website.I adopted the parallel pedagogy for Fall, 2015, so the tests before that will not be the same material as our present curriculum.

Questions about midterm:
– The midterm covers everything we’ve talked about in class, saw in videos, or had in assigned readings (including friction). In short, if you’ve been exposed to it though the class, then please expect that it could be covered on the exam

What about “smart” calculators? You are not allowed to use calculators that graph or can integrate or take derivatives or anything like that… My strong preference is that you use no calculator whatsoever and just estimate… you can write “no calculator” on your exam and I will like it! However, if you feel better about having a calculator, I understand. If you do use a calculator, please find a simple calculator with only trig, square roots and simple math. – Thanks

If you want more practice you can always take more exams. The solutions are on the class websites for these exams.
: Fall 2016 MT#1, MT#1_W16,