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Bring up an ID (any) to borrow an iClicker today.

General Physics I: Day 1 "Everything should be made as simple as possible, but not simpler." ~ Albert Einstein Dr. Jeff Loats. Bring up an ID (any) to borrow an iClicker today. What is Physics?. The study of the fundamental laws of nature… Motion and gravity Atoms & molecules

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Bring up an ID (any) to borrow an iClicker today.

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  1. General Physics I: Day 1"Everything should be made as simple as possible, but not simpler." ~ Albert EinsteinDr. Jeff Loats Bring up an ID (any) to borrow an iClicker today.

  2. What is Physics? The study of the fundamental laws of nature… • Motion and gravity • Atoms & molecules • Light and optics • Electricity & magnetism • Nuclear & particle physics • Astrophysics … and so much more

  3. What Do Physicists Do? Try to determine the laws, which are not known! Experimental Physicist – “The test of all knowledge is experiment.” Test, study, discover… Theoretical Physicist – Look for patterns, generalize and create explanations. Theories are based on experimental hints. Lots of creativity. In industry, physicists and engineers apply the knowledge for inventions and applications.

  4. What Do We “Know”? (no bleeps) The laws of nature we deduce/invent are approximations of the truth. • Experimental results are eternally imperfect, and our imaginations are not infinite. • Science never “proves” that theories are right… but it frequently proves that theories are wrong. The physics we discuss in this class is simultaneously extremely well established and fundamentally flawed!

  5. Physics 2311 – General Physics I Our discussions will mostly be about mechanics, the physics of motion on a human scale. We will work hard on both concepts and solving numerical problems. Critical thinking and problem solving are big! Applying and interpreting will be done all the time.

  6. Dr. Jeff Loats www.msudenver.edu/physics/loats Office: NC 3123F Email: jeff.loats@gmail.com Office hours on my website Email is the best way to reach me

  7. Materials & Participation Required Materials & Equipment • University Physics, 13th editionBy Young & FreedmanVolume 1 (earlier editions ok, extra for MasteringPhysics) • MasteringPhysics access (comes with new book) • iClicker transmitter (bookstore) • Calculator!

  8. WarmUp Assignments (Online) Online assignments due before class, aboutclass Two purposes: • You do reading and get a first exposure • I learn where you stand and customize class Graded on thoughtful effort, NOT correctness Responses will be quoted (anonymously) in class Questions are available 2-3 days before class Due at 10:00 p.m. the night before each class

  9. Worked-Examples & Self-Explanation We are testing a new kind of WarmUp:Worked-Examples with Self-Explanation Prompts (Worked-Examples for short). Your journal has pages for each day of class. There you find a worked-example, followed by self-explanation prompts, followed by an optional practice problem and some room for notes. As part of your WarmUp you will submit a phot of the Self-Explanation Prompts (only). Lets try it…

  10. MasteringPhysics You must have an access code to use this (comes with new text and eBooks, $66 separately). Assignments due roughly once per week Some problems (“Item Type: Tutorial”) have hints. Others (“Item Type: End-of-Chapter”) don’t. MasteringPhysics: • Instant feedback, keeps a record of responses • Work problems in any order • No “submit assignment” button

  11. Adaptive Follow-Up Assignments Software looks at what gave you trouble Chooses up to 3 additional problem sets Due 2 days after the “parent” assignment No late submissions They can earn you some extra credit

  12. What To Expect From Mastering ~20% of students like Mastering at first.  This rises to ~90% by the end of the course.  MasteringPhysics probably improves grades by 5-7% Especially at first, you will likely spend relatively more time on MasteringPhysics homework. This is a different homework system. My advice: • Start early! • Get expert help from me or tutors. • If you can’t come in, email for help!

  13. Website www.msudenver.edu/physics/loats Course Information in three parts PowerPoint Lecture Files Other Handouts Link to UserID Roster system! Link to Warm-Up Assignments! Link to MasteringPhysics!

  14. iClicker Participation Discussion questions using iClickers Participation counts (correctness doesn’t) Cannot be made up Earn two “freebies” at the end of the term…

  15. Components & Grading • Exams & Quiz40% • Comprehensive final 25% • Homework 20% • Warm-Ups 10% • Disc. Participation 5% • Note the expanded A range. • The top and bottom 1% of B, C and D get +/-.

  16. Background Assessment Follow the link on the course website 30 conceptual questions to assess your current knowledge of physics. Has a time limit. Purely a teaching assessment, your score has no bearing on your grade (don’t worry if it is rough). Completing this is required and I am offering extra credit on your first exam for completing it. You have to do this before class on Wednesday, but I ask that you please do it before the reading.

  17. Using iClickers Power button (auto-off after a while). If “Vote Status” indicator flashes ,your response was recorded and confirmed! If “Vote Status” flashes , your response was not received OR the system is not active. Resubmit if you like, it only keeps the last one. Your remote uses radio, no need to point it. green RED

  18. Have you used a classroom response system before? Yes, hardware (iClickers, etc.) Yes, software (PollEverywhere, TopHat, etc.) Nope

  19. What is your class standing? Freshman Sophomore Junior Senior Other

  20. Approximately how much physics have you had before? None 1 semester 1 year More than 1 year

  21. Which best describes the highest level of math you’ve completed? College trigonometry Taking Calculus I this term Calculus I Calculus II I’ve mastered all things differential and integral.

  22. Dimensions Dimensions of a quantity means the type of quantity being measured. Dimension: Money → Units: $, yen, peso, etc. Fundamental dimensions in physics: The first row is the International System (SI units), or the mks system. Use this by default.

  23. Scientific Notation and Prefixes Scales vary hugely, from atoms to stars… Scientific notation makes the numbers easier 602000000000000000000000 → 6.02 × 1023 0.0000000000000000000000000000000000016 → 16 × 10-36 m Prefixes are shorthand for scientific notation. The most common are shown to the right

  24. Precision In The Real World Using a meter stick I claim my height is 1.8475 m Ridiculous on many levels. Maybe 1.85 m So calculate one sixth of my height…. You might tell me that it is 30.833 cm Correct? Sort of… Simplest way to handle this? Significant figures.(one reason to care about this: online homework)

  25. Significant Figures Two kinds of numbers in each calculation: Measured values and perfectly precise values. • Measured values: 1.23 m, 4.667 s, 0.000447 kg Pay attention the number of Sig Figs… • Perfectly precise values: ½, π, 5/2, etc. Assume infinite Sig Figs., (a.k.a. ignore it) So, how do we use Sig Figs? There are two cases: Adding/subtracting Everything else. Going to ignore this

  26. Using Sig Figs • Do the full calculation without rounding: Keep lots of digitsin intermediate steps • At the end, find which input value has the least number of Sig Figs. • Round your final answer to that number of Sig Figs. Some practice?

  27. Sample Problem The four people in a car weigh 140.3 lbs, 48 lbs, 173.0 lbs and 190 lbs. What is their average weight? Are any of these ambiguous in their sig. figs.? Calculate the result of this expression

  28. Where can you find tips for success from previous students in this class? On the Facebook page for this class. On the Blackboard site for this class. On Dr. Loats’ website. On the bottom of your desks, written in gum. “New students should be aware of how important doing the homework actually is, not just for a booster on their overall grade, but a review and recap for the lecture material that assists in many different ways for the exams.”

  29. Problem Solving These steps may not always be necessary but a few of them are critical: Determine what you know Draw something!!!!!! Put in numbers at the end, then do Sig. Figs. Check your answer’s validity

  30. Unit Conversion As you write them down, convert your quantities Best option: The “daisy chain” method: Check that units will cancel Pay careful attention to exponents on units!

  31. Benjamin Franklin was famous for hiding oil in the joint of his bamboo cane and then "calming the waters" of a pond by releasing the oil on it. It turns out that 5 cubic centimeters of oil will spread out and cover half an acre of water. How thick was the oil after doing this? Around 1 nm Around 1 μm Around 1 mm Around 1 cm Needed conversions: 1 acre = 4047 m2

  32. Triangle Trigonometry Our trig. will be all about right triangles. We often work with an angle, which we usually call θ (“theta”). Then… remember the basic trig functions: Then pick the one you need Hypotenuse Opposite θ Adjacent

  33. Find the angle θ in degrees. θ 5.1 m 3.1 m

  34. Vectors: Two Forms First, literally as a magnitude and direction: • 2, due East • 42, 37º N of W • , 129.6667º S of W • Vectors can also be written in component form: • +22.7 (in 1D direction is given by sign) • or (2D) • or 199.22 (3D)

  35. Converting Between Representations Take a vector that is |A| = 15 units long, which is at angle θ = 25° relative to the x-axis, and convert it into component form. Take these components and convert them back into magnitude-direction form. Will the x-component always be associated with the cosine function? No! It depends…

  36. Coming up… Thursday (8/21) → Ch. 1 & 2.1 – 2.3 Your first Warm-Up (for Thursday class) is due Wednesday by 10:00 p.m. Background Assessment link is on the homepage, Due by Tuesday at 9:30 AM First MasteringPhysics assignment:“Intro” is due Saturday by 11:59 PMFirst short homework due Tuesday at 11:59 PM Get an iClicker, register it eventually

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