W16 Mechanics Week 1

We will introduce ourselves and the learning model for this class. We will then introduce the general concepts of the class.
The Codes:
Green is the color or your Goal: What should you know by the end of this day?
Purple is the Reading from the textbook. The textbook is available on the syllabus, which you can find on the main class webpage.

Video Links are in Blue, but turn to purple after you see them.
Red is important

Day 1: Monday
Know how the class is run differently from traditional classes and the resources students have available.
Visit my office sometime this week and say “HI” and consider how nice the 6th floor of Baker Science is to gather in groups. Please make note of when my office hours are (located on class main page), but you can come by to say hi any time – I just might be busy or not there if it’s not an office hour.

Before Monday’s Class:
1. Please get connected with Educanon by watching the videos below. When you hit the link, the video will ask you for your Email and a password and have you enroll in the website for the Winter 2016 class. It’s free. You need to do this to get credit for homework. Please record your password somewhere when you do this. It is not easy to get a new one if you forget your password.
2. Watch the video about the different way we will learn physics: How we are learning physics
3. Watch Veritassium video, Say the Wrong Thing Read more about confusion if you like at NPR: Confusion is How it Feels to Learn
4. Read the syllabus for the class to see how things will work and how you will be graded. The syllabus can be accessed from the main class website.
5. Go to Open Stax College Physics Textbook and decide which format will work for you. The syllabus has some options. But you may want to go to this website to get a more interactive online version.

During Class:
We will introduce ourselves
We will spend a short time discussing the videos. How is this learning format going to work for you?

After Class:
Organize learning resources and prepare for class tomorrow, see below.

Day 2: Tuesday
Units: distance (meters), speed (meters/second), or speed is the time derivative of distance: v=dx/dt, Force (Newtons)
Before Tuesday’s Class:
1. View “Four Concepts” video, 4 kinds of physics questions
2. View Displacement and Velocity
3. Read the introduction to kinematics, dynamics, energy, and momentum:

  • Kinematics: Chapter 2 Introduction and 2.1, 2.3
  • Dynamics: 4.1
  • Energy: Chapter 7 introduction, 7.6
  • Momentum: Chapter 8 introduction, 8.3 (up to figure the first figure, Fig. 8.6)

During class:
We will analyze the 4 scenarios outlined in the video with respect to the other concepts. That is, in the energy conservation scenario (the sling shot), can you describe the dynamics (forces), kinematics (acceleration and speed) and momentum? We will work a problem with good unit analysis together.

After Class:
Distribute problem sets due next Monday and prepare for class tomorrow, see below.

Day 3: Thursday:
We are learning to be conscious of the lens (concept) we are looking through or if we are not using a lens. We are practicing using the four different lenses.

Before Class:
1. View Energy Flows
2. View Acceleration Video
3. Read the introduction to kinematics, dynamics:

  • Kinematics: 2.4
  • Forces, 4.1 – 4.3 Development of Force Concept (Free Body Diagram, Dynamics intro)

4. Consider the cart collision today in class:
1) Is momentum conserved? How do you know?… Or don’t you know?
2) Is energy conserved? How do you know?… Or don’t you know?
3) Are there forces and accelerations? Please describe directions and sizes!
4) What about motion? Can you make a speed vs time graph for each cart? Can you make a displacement vs time graph for each cart? Can you make an acceleration vs time graph for each cart?

We looked at a collision on an (almost) frictionless surface. We know momentum and energy are conserved. However, we also see that this doesn’t mean that kinetic energy is conserved because it can change due to internal forces – in this case friction. After that:

Working in Groups of 3 or 4 students, please do the following:
1) About how many km is in a mile?
2) Convert 1m/s into miles/hour.
3) On a linear track, I start at 10 meters and shuffle forward at 2 m/s. Beverly starts at 40 meters and runs toward me at 4 m/s.
a) How long does it take for us to meet?
b) Make a position-time graph showing each person’s position as a function of time for the entire event.
Beverly and I collide and stick together, completely at rest.
4) Consider the momentum, Energy, Forces, and kinematics in this collision.
5) What do you know about our masses? How come?
6) Are our initial kinetic energies equal? How do you know?

Thursday we look at things falling and compare times to fall and speed at the end. The goal isn’t to answer the question. the goal is to practice using the 4 different concepts and that we are reluctant to use them. Instead of invoking the new tools we are introduced to, we often revert to methods of reasoning that we have used before! The goal is to start using the new tools. Can we examine our inherent familiarity with how physics works in nature; can we see the what something should happen?

Day 4: Friday
LON-CAPA is HERE! As I said in class, I did get it set up for you to log onto immediately after class on Thursday. Please sign up and try the first problem I’ve assigned in Week 1. You will do this by following the directions in this LON-CAPA handout. I’ve assigned 1 question for tomorrow in “week 1”. You have to do it for credit. You don’t have to get it correct. If you just added the course and are not officially on the records, then you may not be able to enroll.

There is an interplay between the concepts of motion, energy, and momentum. We are learning how these relationships are affected by time (rates of change or time derivatives), and forces – how does a force change energy or momentum (how is momentum and energy conserved?).
Before Class:
1.View Forces Effect on p, v, E
2. View Big Picture of Mechanics
3. Read the introduction energy, and momentum:

  • 7.2 Kinetic Energy and Work Energy Theorem
  • 8.1 Linear Momentum and Force
  • 8.3 Conservation of Momentum

4. Do LON-CAPA and come in with questions, notes, comments on Videos and LON-CAPA questions
5. Your first problem set is posted on the main class website. Have a look at it. It is due Monday. I’ll collect it and grade it, but the grade doesn’t count toward your grade in the class. These questions are there to give you an idea of what kind of problems to expect on the final exam and midterms.

In Class… Most folks agreed that the balls would hit the ground at the same distance at the same time. However, is this what happened? Maybe you could try to visualize what would happen. Could you close your eyes and watch the balls roll down the tracks and finish at the same time with the same speed (taking them to the same distance)? Please consider where your logic was incorrect.

Likely, we’ll work on the problem set.

Over Weekend

1. Reflect on “roller coaster” predictions that you made.
2. View Scaling and the Metric System
3. View Pushing Box Problem
4. Read Units 1.2
5. Your first problem set is posted on the main class website. Have a look at it. It is due Monday. I’ll collect it and grade it, but the grade doesn’t count toward your grade in the class. These questions are there to give you an idea of what kind of problems to expect on the final exam and midterms.

Videos I find helpful
Veritasium’s Cool Science Home