Next week we’ll be moving into “Phase 2” of our Learning at Home period. Vanden and the District have been hard at work ensuring that all students have devices and internet connections so your teachers can provide you with more opportunities to learn from home.
The Physics Team has been working hard to prepare lessons that are accessible from home to help everyone of you to have all the knowledge you will need for Biology next year. We are dropping some of the lessons we would normally cover to allow you to focus on this knowledge.
I hope you are safe and healthy at home, and continuing physical distancing to help us pass through this pandemic quickly (stats show California is doing a good job of ‘lowering the curve).
Review of Electromagnetic Spectrum
By now, I hope you all have finished Chapter 18, The Electromagnetic Spectrum and Light. If you are struggling, please take a moment to look back at some of the resources I have posted online to help.
I developed a Kahoot! to help with review. There are 27 questions, and it is open as a “Challenge,” which does not have time limits, and you can take it as many times as you want. You can find it here, or enter 0789319 as the PIN in your Kahoot! app.
I’ll be able to watch how many of you complete it, as well as to see which questions are toughest for many students–then I can post hints/tips for those questions online.
This page last updated at 1:00; more updates coming throughout the afternoon.
Development of rotational kinetic energy and moment of inertia
Remember to watch the video as if you were watching a lecture, but one you can pause, rewind, etc. As you watch the video, take notes and make sure you write down questions you have.
Try out the egg carton hands-on activity at home!
Remember: Moment of inertia (I) can also be thought of as the ‘rotational mass.’
Sample Problems
Sample problem 1
Three 20.0-gram masses are 9.4 cm from an axis of rotation and rotating at 152 revolutions per minute. What is the moment of inertia of the three-object system? The strings holding the masses are of negligible mass.
Solution video
Sample problem 2
Two equal mass eggs are placed at either end in an egg carton of negligible mass. The egg carton is initially rotated about its middle. If the egg carton is now rotated about one end, what is the final moment of inertia of the eggs relative to their initial moment of inertia?
During daily office hours, I will be available to students to connect in ‘real time.’ The main platform I will use will be Zoom, but you can also just phone in to join the Zoom meeting without having to use a Zoom app or the web. It’s just like making a phone call.
For security reasons, the Travis USD has added a required password for Zoom meetings. My password can be found in the yellow at the bottom of this page, listed as Enter this number.
Calling in by phone to a Zoom meeting
Dial 408-638-0968
You will be prompted to enter the meeting ID. My ID is 569-283-4396 (don’t include the dashes) followed by #
If the meeting has not already started and “join before host” is not enabled (I’ll usually not have this enabled), press # to wait for me to open the meeting.
You will be prompted to enter your unique participant ID. Press # to skip this step.
Looking for an opportunity to sit at your computer (not sure if this works well on a phone) and help out life/physical/social scientists? Zooniverse has multiple projects you can join and do actual work. Most projects are tasks that are difficult for computers to automatically complete–the human eye is still better than computers at some tasks. Since multiple people examine each image, you don’t have to worry about making a mistake because others will be reviewing the same image. Projects include tasks like:
Examining photos of distant galaxies and classifying their shape.
Looking for supernovas in photos.
Reviewing images of eyes to help with diabetes research.
Transcribe the military records of African American soldiers in the American Civil War.
Each study includes instructions, and many have practice sessions so you can be sure you are doing the task correctly.
It’s like playing a video game where the results help future our societies knowledge.
From the Zooniverse website:
What is the Zooniverse?
The Zooniverse is the world’s largest
and most popular platform for people-powered research. This research is
made possible by volunteers — more than a million people around the
world who come together to assist professional researchers. Our goal is
to enable research that would not be possible, or practical, otherwise.
Zooniverse research results in new discoveries, datasets useful to the
wider research community, and many publications.
At the Zooniverse, anyone can be a researcher
You don’t need any specialised background, training, or expertise to
participate in any Zooniverse projects. We make it easy for anyone to
contribute to real academic research, on their own computer, at their
own convenience.
You’ll be able to study authentic objects of interest gathered by
researchers, like images of faraway galaxies, historical records and
diaries, or videos of animals in their natural habitats. By answering
simple questions about them, you’ll help contribute to our understanding
of our world, our history, our Universe, and more.
With our wide-ranging and ever-expanding suite of projects, covering
many disciplines and topics across the sciences and humanities, there’s a
place for anyone and everyone to explore, learn and have fun in the
Zooniverse. To volunteer with us, just go to the Projects page, choose one you like the look of, and get started.
We accelerate important research by working together
The major challenge of 21st century research is dealing with the
flood of information we can now collect about the world around us.
Computers can help, but in many fields the human ability for pattern
recognition — and our ability to be surprised — makes us superior. With
the help of Zooniverse volunteers, researchers can analyze their
information more quickly and accurately than would otherwise be
possible, saving time and resources, advancing the ability of computers
to do the same tasks, and leading to faster progress and understanding
of the world, getting to exciting results more quickly.
Our projects combine contributions from many individual volunteers,
relying on a version of the ‘wisdom of crowds’ to produce reliable and
accurate data. By having many people look at the data we often can also
estimate how likely we are to make an error. The product of a Zooniverse
projects is often exactly what’s needed to make progress in many fields
of research.
Volunteers and professionals make real discoveries together
Zooniverse projects are constructed with the aim of converting
volunteers’ efforts into measurable results. These projects have
produced a large number of published research papers,
as well as several open-source sets of analyzed data. In some cases,
Zooniverse volunteers have even made completely unexpected and
scientifically significant discoveries.
A significant amount of this research takes place on the Zooniverse
discussion boards, where volunteers can work together with each other
and with the research teams. These boards are integrated with each
project to allow for everything from quick hashtagging to in-depth
collaborative analysis. There is also a central Zooniverse board for
general chat and discussion about Zooniverse-wide matters.
Many of the most interesting discoveries from Zooniverse projects
have come from discussion between volunteers and researchers. We
encourage all users to join the conversation on the discussion boards
for more in-depth participation.
An humorous video showing the history of the universe. It is mostly correct, although simplified and abbreviated in order to make 12 billion years fit into 20 minutes. The first half focuses on science history, the second on cultural/political/religious history.
Caution: This video includes words like ‘h***’ and ‘f***.’ It also takes a light-hearted approach to religions; trying to treat all equally. No offense is intended. Watch with your own discretion.
Please try to complete all these assignments this week. I will be adding Rotational Energy assignments on Wednesday.
Last updated 3/23 at 11:50. More updates will come later this afternoon. I’ll be on Zoom from Noon until 1:00 if you have questions: Meeting ID: 569-283-4396
Resources
Textbook sections
Read/review the following sections
8.2 Torque and the two conditions for equilibrium
8.3 The center of gravity
8.4 Examples of objects in equilibrium
8.5 Relationship between torque and angular acceleration
If you finish these, our next sections will be 8.6, Rotational energy and 8.7, Rotational momentum
Hopefully you can see how this parallels how we addressed linear motion
Forces, balanced vs unbalanced
Energy
Momentum
Videos
Flipping Physics
Note: Opening the videos below on the YouTube page will provide you with more resources.
Remember: Try writing the problem and solving it as the video proceeds through these steps.
Right hand rule for determining positive or negative torque
We will usually discuss torque as being clockwise or counterclockwise, but in some cases we want to address torque as positive or negative. The “right hand rule” helps you to determine if the torque is positive or negative.
Introductory Rotational Equilibrium Problem
Practice problems
Textbook
Section 8.2-8.4
Straightforward: # 9, 11, 19
Intermediate: # 13, 15, 17, 21, 25
Challenging: None in these sections.
Section 8.5
Straightforward: #29,
Intermediate: # 31, 33, 35, 36
Challenging: None in this section
I’m trying to get free access for students to the “Physics Now” coached problems on the publishers website: www.cp7e.com. I’ll post login information here if I get it.
I’ll post answers to the even numbered questions here by Wednesday, and remember the odd numbered answers can be found her if you can’t find them in your textbook.
TheExpertTA
An assignment has been added to TheExpertTA. The title is 3/20: Torque and Angular Acceleration.
The College Board announced today that the AP Physics 1 test will only include Sections 1-7, which means we only have to complete Section 7 (Rotational Dynamics and Motion) and then move to Section 6 (Simple Harmonic Motion). The tests will be 45 minute, online tests that can be taken from home. They state: “Test security is a concern,” and provide the following pointers:
The exam questions are designed and administered in ways that prevent cheating; we use a range of digital security tools and techniques, including plagiarism detection software, to protect the integrity of the exams.
Scoring at-home work for an AP Exam is not new to the AP Program. For years the AP Program has received and scored at-home student work as part of the exams for the AP Computer Science Principles and AP Capstone courses.
If you are on Twitter, you can get the latest official updates by following @AP_Trevor.
We will continue to study all section of the curriculum after we have finished 1-7, and reviewed for the test, but this material will not be on the AP test.
Today’s assignments
coming soon, I wanted to post the College Board announcement ASAP.
Waves review video, with introduction to electromagnetic waves
The equation E=hf you do not need to know, but the relationship shown by the wave (the higher the frequency, the higher the energy) you should understand conceptually.
How is the speed of light measured?
This video is a bit long, but it explores how we determined the speed of light (as shown on page 534 of your textbook). This embeded video is set to start with how they first measured the speed of light. The rest of the video is optional, but available for those who might be interested.
Physics girl describes electromagnetic waves
https://youtu.be/4e8HT3GGw6c
Minute Physics
These two one-minute videos demonstrate the “Wave or Particle” discussion presented on page 536.
This one is a bit harder to understand.
In the end, however, we don’t say electromagnetic waves are waves or particles: They are simply electromagnetic radiation, which sometimes acts like a wave and sometimes like a particle. It’s sort of like asking if water is a solid or a liquid: In different situations it can be a solid, but in others it’s a liquid.
Online resources
ck-12 Light waves simulation
This simulation offers you plenty of options to investigate electromagnetic waves. This should help with understanding the chapter.
PhET simulation
PhET provides a great simulation to experiment with radio waves and electronmagnetic fields. This version runs with Java only, so it won’t run on phones. If Java is not installed on your computer, and you wish to install it, instructions are here for Macs and Windows.
Last updated at 1:30; I’ll be adding more between now and 6:00 pm.
Today’s Zoom meeting at Noon
This meeting is optional, but I’ll be online if you have questions. Log into Zoom and use the Meeting ID 569-283-4396.
Quick internet access survey
Please complete this short survey to let me know about your internet access. This will help me know how much I can depend on your access to this website and the resources I share here. All answers are anonymous.
New online homework system
While homework is not required, I have set up an account with TheExpertTA.com to provide practice problems that are graded as you work them, along with tips (some of my past students have said many of the tips aren’t that helpful, but they are there. TheExpertTA is generously providing free accounts for the rest of the semester due to the COVID-19 crisis.
You can sign up for the class here: http://goeta.link/USB06CA-51F289-21B . Email me if you have troubles logging in, and hopefully we can work it out.
We’ll keep learning physics while we are home; I’ll be posting assignments and resources online daily.
General Resources
Zoom meetings
Starting on Tuesday, I will hold a Question and Answer session via Zoom (an online video platform) from Noon until 1:00. (If I get too many AP and 9th grade students, I may break into two sessions, one at noon and one at 1:00, but I’ll announce that later if it happens.)
Zoom requires an app for your computer or phone, but the company has a great reputation and is not full of ‘bloatware.’
You can visit Zoom on the web here, or using a phone app you can enter this Meeting ID: 569-283-4396
I think you need to create a Zoom account to join a meeting but you can use your login in the future as well. I suggest you create a Zoom account even if you aren’t required to.
Due to the COVID1-19 emergency, Zoom is allowing free student and teacher upgraded accounts for the rest of the spring.
