1 / 26

Welcome to Physics 102!

Welcome to Physics 102!. Electricity + Magnetism Optics Atomic Physics Nuclear Physics Relativity. Please turn cell phones off. Meet the Lecturer. Alan Nathan a-nathan@uiuc.edu Research Experimental Nuclear/Particle Physics Physics of Baseball

Télécharger la présentation

Welcome to Physics 102!

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Welcome to Physics 102! • Electricity + Magnetism • Optics • Atomic Physics • Nuclear Physics • Relativity Please turn cell phones off Physics 102: Lecture 1, Slide 1

  2. Meet the Lecturer • Alan Nathan a-nathan@uiuc.edu • Research • Experimental Nuclear/Particle Physics • Physics of Baseball • see http://webusers.npl.uiuc.edu/~a-nathan/pob • Office Hours: Monday 11-12 • or drop in any time and I’ll talk with you if I am not otherwise tied up 04 Physics 102: Lecture 1, Slide 2

  3. Course Format • http://online.physics.uiuc.edu/courses/phys102/spring08/ • Daily Planner • what you should be doing and when you should be doing it • Course Description • Lectures • posted just after the lecture is given Physics 102: Lecture 1, Slide 3

  4. Course Philosophy • Read about it (textbook and prelecture) • Untangle it (lectures) • Play with it (labs) • Challenge yourself (homework) • Close the loop (discussion/quiz) the order is important! Physics 102: Lecture 1, Slide 4

  5. Course Format(Spiral Learning) • Preflights 50 • Homework 100 • Lab (Prelab due at start of lab) 150 • Discussion 150 • Take-home quizzes; drop lowest 1 • Hour Exams (3 x 100) 300 • Final Exam 250 1000 07 Physics 102: Lecture 1, Slide 5

  6. 950-1000 A+ 920-949 A 900-919 A- 880-899 B+ 860-879 B 835-859 B- 810-834 C+ 780-809 C 750-779 C- 720-749 D+ 690-719 D 610-689 D- <610 F Grading Scale Physics 102: Lecture 1, Slide 6

  7. Prelectures & Lecture • Do it! • Answer preflights 50/1000 points • 1 point for honest attempt at preflight. • 1 point for using clicker in lecture (75%) • 2 points/lecture x 25 lectures = 50 points 10 Physics 102: Lecture 1, Slide 7

  8. P102 Lectures • Not everything you need! • Lectures: Concepts, Connections, Motivation • Textbook: Comprehensive • Homework + Discussion: Calculations • Lab: Hands-On • Taking Notes • Lecture notes are available at bookstore or online • Some key pieces for you to fill in 15 Physics 102: Lecture 1, Slide 8

  9. Content Physics 101 Physics 102 • Kinematics • Forces • Energy • Fluids • Waves (Sound) Macroscopic Microscopic • Electricity+Magnetism • Circuits • Optics • Modern • Atomic • Nuclear • Relativity 18 Physics 102: Lecture 1, Slide 9

  10. Origin of Charge • Charge is an intrinsic property of matter • Two types: • Positive Charge: Protons • Negative Charge: electrons • Opposite charges attract. Like charges repel. • Atoms are neutral • Negatively charged electrons “orbit” r~10-10 m • Positively charged central nucleus r~10-15 m 20 Physics 102: Lecture 1, Slide 10

  11. Q: How do electrons behave in a perfect conductor? Q: How do electrons behave in a perfect insulator? Conductors and Insulators Most things are in between perfect conductor / insulator 23 Physics 102: Lecture 1, Slide 11

  12. Electroscope • Conduction • Charged rod is brought near scope • Charged rod touches scope transferring some charge • Scope is left w/ same charge as rod • gold leaves repelfly apart 27 Physics 102: Lecture 1, Slide 12

  13. Electroscope • Induction • Charged rod is brought near scope • Scope is briefly grounded allowing charge to flow on (or off) scope • Scope is left w/ opposite charge as rod 27 Physics 102: Lecture 1, Slide 13

  14. ACTS • A negatively charged rod is used to charge an electroscope by induction. What is the resulting net charge on the electroscope? A) positive B) zero C) negative • If the conducting electroscope were replaced by an insulating ball and then charged by induction as above, what would be the net charge on the ball. A) positive B) zero C) negative 32 Physics 102: Lecture 1, Slide 14

  15. Qp=1.6x10-19 C Qe = -1.6x10-19 C + - r = 1x10-10 m Example Coulomb’s Law • Magnitude of the force between charges q1 and q2 separated a distance r: F = k q1q2/r2k = 9x109 Nm2/C2 • Force on electron in Hydrogen atom 34 Physics 102: Lecture 1, Slide 15

  16. Qp=1.6x10-19 C Qe = -1.6x10-19 C + - r = 1x10-10 m Example Coulomb’s Law F = k q1q2/r2 k = 9x109 Nm2/C2 F= 2.3x10-8 N 35 Physics 102: Lecture 1, Slide 16

  17. qp=1.6x10-19 C qe = -1.6x10-19 C + - r = 1x10-10 m F ACT: Coulomb’s Law • What is the direction of the force on the proton due to the electron? (A) Left (B) Right (C) Zero • What is the magnitude of the force on the proton due to the electron? Example F= 2.3x10-8 N 38 Physics 102: Lecture 1, Slide 17

  18. ACT A positive and negative charge with equal magnitude are connected by a rigid rod, and placed near a large negative charge. What is the net force on the two connected charges? A) Left B) Zero C) Right Positive charge is attracted (force to left) Negative charge is repelled (force to right) Positive charge is closer so force to left is larger. - + - 43 Physics 102: Lecture 1, Slide 18

  19. ACT: Induced Dipole • An uncharged conducting sphere is hung next to a charged sphere. What happens when the uncharged sphere is released? 1) Nothing 2) Attracted to charged sphere. 3) Repelled from charged sphere. 45 Physics 102: Lecture 1, Slide 19

  20. ACT: Induced Dipole • An uncharged conducting sphere is hung next to a charged sphere. What happens when the uncharged sphere is released? 1) Nothing 2) Attracted to charged sphere. 3) Repelled from charged sphere. Physics 102: Lecture 1, Slide 20

  21. ACT: Induced Dipole • An uncharged conducting sphere is hung next to a charged sphere. What happens when the uncharged sphere is released? 1) Negative charge attracts + repels - Physics 102: Lecture 1, Slide 21

  22. ACT: Induced Dipole • An uncharged conducting sphere is hung next to a charged sphere. What happens when the uncharged sphere is released? 1) Negative charge attracts + repels - 2) Since + is closer, attractive force is strongest Physics 102: Lecture 1, Slide 22

  23. ACT: Induced Dipole • An uncharged conducting sphere is hung between a charged sphere and a grounded sphere and held midway between the two. What happens when the uncharged sphere is released? • An uncharged conducting sphere is hung between a charged sphere and a grounded sphere and held midway between the two. What happens when the uncharged sphere is released? 1) Negative charge attracts + repels – 2) Since + is closer, attractive force is strongest Physics 102: Lecture 1, Slide 23

  24. ACT: Induced Dipole • An uncharged conducting sphere is hung next to a charged sphere. What happens when the uncharged sphere is released? 1) Nothing 2) Attracted to charged sphere. 3) Repelled from charged sphere. Physics 102: Lecture 1, Slide 24

  25. Summary of Today’s Lecture • The concept of charge • Conductors and insulators • Coulomb’s Law for the force between charges • Much more on Coulomb’s Law in next lecture Physics 102: Lecture 1, Slide 25

  26. Prior to next lecture…. • Read Sections 16.1-6 • Do your prelecture and preflight before 8:00 AM on the day of lecture. See you Wednesday! Physics 102: Lecture 1, Slide 26

More Related