Physics 201

Welcome to Cornell's Physics 201, Why the Sky is Blue. Lectures are on Tuesday and Thursday at 2:55 pm in Rockefeller Hall, Schwartz Auditorium. Recitation sections are all on Wednesday at 9:00 (#5), 2:30 (#'s 1 & 2) and 3:35 (#'s 3 & 4).

We will be using an instant response system during lecture. Make sure you have your I-clicker which you can purchase in the bookstore. You will be expected to have it with you at all lectures.

To register your I-clicker, go to : I-clicker registration


Course instructor is Prof. Ahren Sadoff (ajs50@cornell.edu). Phone: 255-4882 (Wilson Lab), 255-7162 (Clark Hall office)

Office hours: Room 111, Clark Hall, 1:30--2:30 Tuesday and Thursday (or by appointment)

Teaching Assistants are:

• (sections #1, #3,) Jesse Hopkins jbh246@cornell.edu Office Hours:Tu. 1:30-2:30, Wed. 9:30-10:30, Th. 4:15-5:15. Or by appointment Room-- Clark 130
• (sections #2, #4) Zach Lamberty rl373@cornell.edu Office Hours: Tu. 12:50 - 1:50, Wed. 4:30 - 5:30. Or by appointment. Room -- Rock B81
• ( #5) Ines Firmo iaf6@cornell.edu Office Hours: Tu, Wed. 10:00 - 11:00. Or by appointment Room -- Rock B83

Books on reserve in the Physical Science Library-- Second floor, Clark Hall

• Conceptual Physcis by Paul Hewitt
• Physics: Concepts and Connections by Art Hobson

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Reativity Videos; Click on the desired title:

• Speed of projectiles and waves
• Michelson Morley Experiment
• Relativity of Simultaneity
• Time Dilation
• Length Contraction
• Doppler Effect and Twin Paradox

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• In-Lecture quizzes, before first prelim
• In-Lecture quizzes, before second prelim

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Prelim II Review session schedule:

• Tuesday 11/10: 5:30 -- 6:30, Rock 127, Ines
• Wednesday 11/11: 5:30 -- 6:30, Rock 127, Zach
• Wednesday 11/11: 8:00(pm) -- 9:00, Rock 102, Jesse
• Thursday 11/12: 1:15(pm) -- 2:15, Clark 111, A. Sadoff

Note: Calculators will be needed for the final exam, but not for Prelims 1 or 2

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Practice Prelims:

• practice prelim 1, click here
• practice prelim 2, click here

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Preliminary Exams and Final Exam schedule

All examinations will be in Schwartz Auditorium during class time unless otherwise noted

• Prelim I : Thursday, Oct. 8 ----cofirmed
• Prleim II: Thursday, Nov. 12 ---confirmed
• Final Exam: Wed. Dec. 16 --- 7:00 to 9:30 pm

Homework Assignments and Review of Key Ideas

Homework is due at the beginning of next week's Wednesday recitation section after assigned.
Readings are from Prof Sadoff's book "Questioning the Universe"

• Week 1, Aug. 27 -- Sept.2
  • Reading Assignment: Preface, Chapters 1 , 2
  • Written assignment #1 (due Sept 2): Ch 1: Questions 5,6,7. Plus -- write 3 questions you have about the physical universe.
  • Key Ideas: Definition of physics and assumptions, Methodology of Science: experimentation (control of variables), need a quantatative description of Nature
  
  
• Week 2, Sept. 3 -- Sept.9
  • Read: Chapters 2 , 3 ; No written assignment
  • Key Ideas:Theories: what are they, can they be proven? Aesthetic judgements. Motion-- why begin with this ?, variables to describe motion, defintion of v and a, scalars and vectors, graphs of 1-dimensional motion for constant v and constant a;
  
  
• Week 3, Sept. 10 -- Sept.16
  • Reading Assignment: Chapter 4
  • Written Assignment #2 (due 9/16): Ch. 3; #'s 7,11,12,13,15,16,17, 9( a,b,c,d) (do last)
  • Key Ideas: 2-dimensional motion -- in circular motion the acceleration vector points radially inward.Forces: The Four Fundamental forces; specific force law---Gravity; What does the equation tell us ? Newton's 2-nd law; What is the meaning of F ? Combining Newton's 2-nd law and the law of Gravity; What is the result ? The mass of the Earth; how do we find it ?The Cavendish experiment.Newtomian mechanics; Newton's 1-st, 2-nd and 3-rd Laws of motion. Effect of Newtonian ideas on society
  
  
• Week 4, Sept. 17 -- Sept. 23
  • Reading Assignment: Chapters 5,6
  • Written Assignment: Pendulum Experiment (due 9/23)(handed out in lecture. If you did not get your copy, please get in touch with your TA who will be able to mail you an electronic copy of the assignment)
  • Key Ideas:. Electricity and Magnetism:Electric force law, Ampere's law,Faraday's law.Where are the moving charges in a bar magnet? Non-contact forces. How do we understand them ?--- The Field concept vs Action-at-a-distance.
  
  
• Week 5, Sept. 24 -- Sept. 30
  • Reading Assignment: Chapters 6, 7
  • Written Assignment: None
  • Key Ideas: Evidence for the Field concept ? Are there really contact forces after all? The Character of Physical Laws: Causality, The Prime Directive, Symmetry, "Tranlslation" and "reflection" symmetries. Some symmetries are "broken"-- that's good for us !!
  
  
  
• Week 6, Oct. 1 -- Oct.7
  • Reading Assignment: Chapter 8
  • Written Assignment: Assignment #4, Momentum and Energy Conservation (due 10/15) Chapter 8: 4,7,9,14,16,17,22,24,27(omit f)
  • Key Ideas: Conservation Laws --- due to some symmetries. Momentum and the Law of Conservation of momentum. Conservation of energy. Energy comes in different forms. Conversion of one form into another-- especially Kinetic Energy into Potential Energy and vice-versa
  
  

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  Prelim I on Oct. 8, Fall Break Oct.10 -- 13

  
  
• Week 8, Oct. 15 -- Oct.21
  • Reading Assignment: Chapter 9,first part of Chapter 10:10.1-- 10.4
  • Written Assignment: optional make-up Pendulum experiment(due 10/21)
  • Key Ideas: The Atom; the history of different atomic models,atomic spectra-- the atom's "fingerprints"Details of the Atom, Atomic Spectra, Definition of the Electron Volt(eV and MeV) and different energies in eV(and MeV) units. The Nucleus: constituents, what holds it together, decays-- Alpha, Beta and Gamma,
  
  
• Week 9, Oct. 22 -- Oct. 28
  • Written Assignment: #5: Ch 10: 1,6,11,13,21(include Beta+ decays) (due. 10/28)
  • Key Ideas: Half life, Carbon dating:how it works, assumptions and verification.The Beta Decay story.
  
  
  
• Week 10, Oct. 29 -- Nov.4
  • Reading Assignment: Chapter 10.5 (The Beta decay story), Chapter 12:12.1-- 12.3
  • Written Assignment #6:Ch 10: 28,29,31,33,34,39 (due 11/4)
  • Key Ideas: Introduction to Relativity: Galilean Relatvity, v = v' + u (addition of speeds). The Principle of Galilean Relativity, Inertial reference frames, Maxwell and light is a wave, the difference in measuring the speeds of particles and waves, measuring the speed of an airplane through the air. The Ether--- a universal medium. What is the speed of the earth through the Ether ? Can we measure it in a similar manner to the pilot in the airplane ? Why not ?, the Michelson-Morley experiment--- what did it try to measure ? How did it try to do it ? What was observed ?
  
  
  
• Week 11, Nov.5 -- Nov. 11
  • Reading Assignment: Chapter 12: 12.4--12.8.1
  • Written Assignment #7: Relativity I--- Ch 12: 7,9,10,11(a,c),12(b,e,f,g,h,i),13,15,22 (due 11/11)
  • Key Ideas: What are the explainations for the observation in the MM experiment ? Which one do we believe to be correct ? A consequence of the speed of light being the same for all observers; can 2 = 1 ?? A simple experiment for two observers moving wrt each other to measure the speed of light --- what was the matter with the analysis ? The three assumptions -- what are they ? The Postulates of Special Relativity, The Relativity of Simultaneity
  
  
  

  Prelim II on Nov. 12

  
  
• Week 12, Nov.17 -- Nov. 18
  • Reading Assignment: section 12.8.2
  • Written Assignment: Assignment #8, Relativity #2 ,Ch 12: 35,37,38,39,40(Due Nov. 24 in lecture)
  • Key Ideas: Time Dilation, proper time vs. "Dilated time", the variables beta and gamma, Length Contraction, proper length vs. "Contracted length",
  
  
• Week 13, Nov. 19 -- Nov. 24 ( Happy Thanksgiving )
  • Reading Assignment: finish chapter 12
  • Written Assignment: Assignment #9, Relativity #3, Ch.12: 41,44,45,46,47,48(Due Dec. 2)
  • Key Ideas:More on Length Contraction, The Relativity of Simultaneity is crucial in understanding this. Was Lorentz right after all ? Other relations involving gamma; Energy and mass. E=mc2 . Back to addition of speeds equation-- Einstein gets it right. Doppler Effect, expansion of the Universe, Twin Paradox. The car in the garage paradox.
  
  
• Week 14, Dec. 1 -- Dec. 3 ( last week )
  • Reading Assignment: Chapter 11
  • Written Assignment: Term Essay (Will be handed out in class, Due Wed. Dec. 9 to your TA by noon)
  • Key Ideas: The nature of light; properties of waves and particles. Interference and diffraction. Is light a wave or a particle ?--- demonstrations. Why the Sky is Blue. The Electromagnetic spectrum and what is "waving".