Week 6 121 W2020

THIS WEEK! Self Intervention on Empathy

Many of you know that I have a split focus at Cal Poly: Intro Physics and Sustainability/Energy/Global Poverty. The second focus involves my research and two classes that I introduced in 2007: Appropriate Technology, Development, and Appropriate Technology, Design. In these classes, we have three “self interventions” whereby we change something about our lives and log the experience. If you like, you can read about the “don’t throw anything away for a week” self intervention. However, we as a class are going to take part in the “Empathy Self Intervention“. Please go to the website. You have until next Monday to send me your experience. You may ask what this has to do with physics… but doesn’t it? As we learn to explore lenses, we may become more effective by reminding ourselves that our knowledge is not complete (as stated in the syllabus), and that it is beneficial to look at the world through other lenses. Please think about this and log the experience sometime this week starting Tuesday.

Monday: Angular Dynamics and Statics.

Master the use dynamics (vector sum of the torques = I * alpha) just as you did for force and acceleration in linear motion
Augment your use of Work-Energy Theorem with rotational kinetic energy.

Before Class:

  • Watch the videos: Torque and the Lever
  • Read 4.5 about finding moment of inertia
  • Students in the past found the moment of inertia video difficult. Please understand that the second half of the video deals with integrating the mass, which you are not responsible to know.
  • Read 4.6, introduction to statics.
  • Then watch the video about the standard diving board problem
  • Be mindful of your tendency to “otherize” someone. If you catch yourself, enact your self intervention (as described above). Document the experience and send it to me.

In Class
Hand in PS #5

After Class

Tuesday: Angular Dynamics and Statics.

  • Please watch this video on torque = time derivative of angular momentum
  • Please read 4.7 Intro to Angular Momentum
  • I want you to be aware of one thing: just like F=ma, for rotational problems we use Torque = I*alpha. Please identify in your problem set which questions involve this Rotational Dynamics. Then, please describe a protocol for rotational dynamics (Forces) that is a rotational analogue of our protocol for linear dynamics.
  • I ask you to be prepared to “think with your hands”. Please see this NPR article that shows students who take notes by hand retain more information than students who type notes into a computer. My inference (which may not be correct) is that if you did neither, then you’d retain even less.
  • Did you know that studies indicate texting costs students an average of half a letter grade in their classes. Should we do something about this? NPR story about cell phones and classes
  • Check out PS#6 on main class website. Due next Tuesday.
  • Solutions to Assessment #5 posted! Some great work from you all.
  • PS#5 Solutions posted.


Wednesday: Centripetal Acceleration, gravity and inverse square law

we look at universal gravity and the inverse square law.

  • Please read 5.0, Centripetal Acceleration
  • Watch derivation of Centripetal Acceleration and how to use it.
  • Check out PS#6 on main class website. Due next Tuesday. Do as much as you can… or at least the stuff that might prepare you for the assessment!
  • Solutions for PS #5 posted.

During Class:

  • Assessment #5
  • Forces cause Centripetal Acceleration!

circular dynamics with more than one force. It’s just like the elevator problem, but the acceleration is centripetal acceleration.
Before Class

  • I’m grading the the assessments: heavy carnage. Folks haven’t yet made a clear distinction of rotational motion (and variables) from linear motion. We are reverting again to linear motion (in uniform circular motion caused by a linear force) for a while, but we will return to rotational motion, so please go back and practice this stuff. From what I’m seeing, I’m betting that many of you don’t have the correct rotational relationships on your formula sheets. Please consult the first page of chapter 4 and make sure you see how these equations are exact analogs to the linear equations… but different.
  • Finish project #1… to be collected on Thursday next week – but you can hand them in sooner to get them back sooner. It usually takes three times before student groups get an “A”. I think this is the learning process. However, if you get it right on the second try, we win!
  • Please read 5.1 Inverse square relations (if you didn’t do it already).
  • See video on Universal Gravity and Inverse Square Law
  • Read 5.2 Universal Gravity
  • Veritassium music gravity video
  • Be mindful of your thoughts. If you dehumanize someone, invoke the empathy self intervention. See the directions on the main class website.
  • Watch video: There’s No Such Thing as Centripetal Force, or Centrifugal Force
  • Send me your self intervention by next Monday, please
  • Our final exam time: We could have our final on one of the following times if we can all agree.
    • in our classroom
      • 1-4 on Friday (our official time),
      • 4-7 on Thursday (a time that you must all have open because we also meet TR,
    •  in Baker Science 261, 262 – really nice rooms (because the rooms are open during this common final time)
      • 7-10 Wednesday,
      • 7-10 Tuesday.

During Class

  • We can talk (for a SHORT period of time) about options for the final exam.  Please think about it first and we’ll take a short vote.

After Class

  • Send me your self intervention by next Monday, please