Physics 114

1. Physics 114 Professor: Rick Matthews, matthews@wfu.edu 217 Olin Physical Laboratory http://www.wfu.edu/~matthews http://www.webassign.net Come down and ask for POI’s if needed • Topics Covered • Electricity and Magnetism • E&M Waves • Optics • Nuclear Physics Please Pick Up and READ the Syllabus

2. Reading Assignments and Quizzes Reading Assignments. Required before you come to class. Reading quizzes, due 7am before every lecture; starting Wed A few submissions per problems Work by yourself

3. Homework and Semester Quizzes Homework Assignments Required: Every Lecture Starting Monday Several Submissions Encouraged to work with others, but you must submit your own work.

4. Webassign • http://www.webassign.net/student.html • Username is your email (without @wfu.edu) • Institution is wfu • Password (if new to webassign) is your student number/ There is a test homework on using webassign. Log into webassign ASAP. If you have difficulty, contact me.

5. Web Information • How to access course info: • Go to www.wfu.edu/~matthews • Click on teaching, and then the link to this course. • There will be a page for general announcements, and a sidebar filled with useful information including lecture notes. • This course does not use blackboard.

6. Web Information • How to access course info: • Go to www.wfu.edu/~matthews • Click on teaching, and then the link to this course. • There will be general announcements, and useful information including lecture notes. • This course does not use blackboard.

7. Goals • Learn the concepts of physics; • Learn what science is and how science progresses; • Learn to explain many everyday phenomena; • Learn to think analytically and logically; • Learn to articulate scientific arguments; • Find the world a more interesting place. Toward that end, physics concepts will presented in the context of real-world examples, applications, and demonstrations. You will learn to explain many things around you using only a few fundamental concepts. You will discover that science is a process, rather than a set of results. The class will be highly interactive, as we seek to do science. We will develop models and theories, based on observation of classroom demonstrations.

8. Text • Serway and Jewitt, Physics for Scientists and Engineers, 6th edition.

9. Tutorials • Regularly scheduled tutorial sessions will be announced that will provide opportunities for help in working problems or understanding concepts.

10. Laboratory • A weekly laboratory is an important part of this course. • You must pass the lab to pass the course. You must pass the lab to pass the course. You must pass the lab to pass the course. • Your lowest lab grade is dropped. This means a single absence from lab would not significantly affect your grade. There are no make-up labs, so save this for an emergency. Please see the accompanying document on laboratory grading. Be sure to bring your lab manual to every lab.

11. Hour tests Three tests are given during the course of the session. Alternate test times are normally given only in the event of infirmary confinement. Please notify me of such a problem prior to the test. Test dates: • Sept. 18. • Oct. 18. • Nov. 17.

12. Final exam The final examination will be given only at the regularly scheduled time as specified in the class schedule published by the Registrar's Office. There will be no alternate exam times.  Please notify your siblings not to have wedding rehearsals on this date. Please notify your grandmother that you cannot attend her retirement dinner at this time

13. Grading Your final grade will be composed of the following contributions: • Final exam: 25%* • 3 Tests: 50%* • Homework: 15%** • Lab: 10% *** You must pass the lab to pass the course.

14. Office hours • 9:00 - 10:30 a.m. Tuesday • 9:00 - 10:30 a.m. Thursday If these times do not work for you, call or e-mail me. Aside from class time and meetings, I am generally in my office from 8:30 – 6:00, Monday – Friday.

15. Coordinate systems Different ways of representing space, and physics. Some problems are easier in some coordinate systems, but the physics is invariant. Cartesian Coordinates:

16. Polar Coordinates Another popular coordinate system, along with cylindrical and spherical

17. Vectors and Scalars Vectors: Magnitude and direction Scalars: Magnitude Displacement is a vector. Velocity is a vector. Acceleration is a vector.

18. The x- and y-components of a vector: The magnitude of a vector: The angle q between vector and x-axis: Vector Components: Geometric

19. A unit vector is a dimensionless vector having a magnitude 1. • Unit vectors are used to indicate a direction. • i, j, k represent unit vectors along the x-, y- and z- direction . • is another common notation. • i, j, k form a right-handed coordinate system. Vector Components: Algebraic A = Axi + Ayj

20. Rx = Ax+ Bx Ry = Ay+ By The components of R: Vector Addition: Algebraic I We want to calculate: R = A + B From diagram: R = (Axi + Ayj) + (Bxi + Byj) R = (Ax + Bx)i + (Ay + By)j

21. The magnitude of R: The angle q between vector R and x-axis: Vector Addition: Algebraic II

22. Parallel and Antiparallel Vectors There are two ways (in 2 or 3D) to multiply vectors. Scalar product -> two vectors make a scalar Also called the dot product or the inner product Vector product -> two vectors make a vector Also called the cross product or the outer product

23. Scalar Product Scalar product -> two vectors make a scalar Geometric Algebraic

24. Vector Product Vector product -> two vectors make a vector Geometric C has magnitude absinq. Direction perpendicular to the plane containing A and B. Algebraic

25. The right hand rule Force F velocity v Magnetic Field B

26. Electricity and Magnetism • One of the four fundamental forces of nature • Responsible for the vast majority of what we observe around us • Probably best-understood and best-tested of the forces of nature • Electromagnetic Interactions: • Electricity and Electronics • Magnetism • Chemistry • Biology • and even more

27. Electrical Charges • Electric forces only affect objects with charge • Charge is measured in Coulombs (C). A Coulomb is a lot of charge! • Charge comes in both positive and negative quantities • Charge is conserved – it can neither be created nor destroyed • Charge is usually denoted by the letter q. • An object has a total charge of 5 mC. It is divided into two pieces, one of which has charge 8 mC and the other of which has charge • 3 mC • -3 mC • 13 mC • Such a division is impossible

28. Matter and Charges • All matter is made of positive and negative charges (or neutral) • An object’s total charge is very close to zero • When an object becomes charged, a tiny fraction of its charged particles (usually electrons) are lost or gained • These particles (usually electrons) can flow through objects • Some materials are better at allowing the flow of electrons than others Insulator A material that resists the flow of electrons and other charged particles Conductor A material that allows electrons or other charged particles to flow freely

29. Elementary Charge • Charges seem to come only in integer multiples of a fundamental charge unit called e • We will treat e as a positive number (some sources treat it as negative) e = 1.602  10-19 C Particleq Proton e Neutron 0 Electron -e Oxygen nuc. 8e Calcium ion 2e Chlorine ion -e know these