For students enrolled in an introductory physics lab, PHYS 2108 and PHYS 2109 lab classes begin this week (Jan. 14-18). You must attend the first week class or send an email to lab@phys.lsu.edu PRIOR TO CLASS explaining your absence or you will be dropped from the course. Ray Chastain Supplemental Instruction The very first SI session will be Thursday January 17th in Allen 39 at 5:00 pm Every session after that will be: Sunday 4:30-6:00 Wednesday 5:00-6:30 We don't have a location established as of now. I will email that out as soon as I get it. Ryan Gibson
Rongying Jin (professor) Department of Physics & Astronomy Office: 229B Nicholson Hall Email: rjin@lsu.edu Tel: (225) 578-0028 Visit my personal website for more information: http://www.phys.lsu.edu/rongying/
You are Science & Engineering Majors. You are registered for PHYS 2101. You want to learn PHYS 2101?? You want to have good grade!!
Spring 2013: PHYS2101 Section 9&14 Reading Assignments: Lecture schedule is provided - read material before lecture! Lectures: Concepts will be developed through the lectures, demonstrations and class discussion Homework: Best way to learn the material: -- Quizzes & Exams mostly based on HW
Class Information is also via WebAssign HW will be due in 1 week! Start early!! WebAssign will handle most of your class-related needs: homework, formulae sheets, practice tests http://webassign.net/student.html IMPORTANT: Try to log into WebAssign TODAY Click I have a class key then input your class key: lsu 8522 3194. If you have used WebAssign before, your old password will be in effect If you have NOT used WebAssign before, you can logon in by using your LSU PAWS email address without the @lsu.edu, and setup your own password. If you have a problem in logon, please check: (1) username (has to be PAWS username); (2) if you have paid for accessing WebAssign; (3) if you are in my class roster. Please contact me if you cannot logon. The first homework assignment is posted.
Course details -- see syllabus Class Format - Announcements - Mixture of Power Point and Chalk Board/Overhead - Some theory. Some problems - Power Point slides are available on class website & my own website - Please ask questions (and correct me!). Course: It is assumed that everyone has credit in PHYS 1100 so the material in Chapters 1-6 (vectors, 1- and 2-D kinematics, Newton s laws) will only be reviewed in the first week of class. If you tested out of PHYS 1100, you will be assumed to know this material and should review it carefully if you don't remember it well. You will be tested on this material in the second week of class. After the first two weeks the course assumes a more normal pace and will cover most of the section contained in chapters 7 20, with the exception of chapter 17, which will be skipped. The core material of the course covers concepts in mechanics, fluids, wave motion, and thermodynamics. The lecture schedule will specifically indicate sections of text that are covered on a given week. Students should read and become familiar with this material before coming to class. Course grades will be determined by quizzes (mostly in weekly base), Homework, four 1-hour mid-term tests, and a final (see following).
Course details -- see syllabus Homework: Homework assignments will be posted online at: http://webassign.net/student.html (details announced in class). They are similar to text book HW. Except when noted in class, due dates for homework assignments will generally be midnight on Monday after the assignment. Full solutions will be available at webassign after the due date. Quiz: There will be a quiz (10-15 min.) based primarily on the HW problems due that week. Tutoring: If you do not understand the material or you experience difficulty in working the problems, seek help from the graduate tutors in Room 102 of Nicholson Hall. This service is free. There will be 2101 Supplemental [Sunday 4:30 6:00 pm, Wednesday 5:00 6:30 pm), which is also free. More information coming soon. Make sure you take advantage of the instructor office hours posted. You should feel free to go to any instructor's office hours if you have class conflicts with your own instructor's office hours; all sections follow the same schedule and use the same homework assignments.
Course details -- see syllabus Exams: There will be four 1-hour mid term exams. There will be no make-up exams: if you need to miss an exam for a university-scheduled function, make sure you obtain permission from your instructor in advance. If you miss an exam with permission your other scores will be adjusted. Exams will contain a combination of multiple-choice questions and work problems for which you must show your work. The scheduled dates for exams are as following: Exam 1 100 points February 5, 2013 6 7 pm TBA Exam 2 100 points March 12, 2013 6 7 pm TBA Exam 3 100 points April 9, 2013 6 7 pm TBA Final 200 points May 9, 2013 3 5 pm TBA Students having three or more final examinations in a 24 hour period may request permission to take no more than two examinations on the day concerned. These requests must be requested by the student and approved by the instructor before Friday April 9 th. A formula sheet will also be provided and no other material is to be used during the exam. You will need a scientific calculator; graphic calculators are fine, but not necessary. Old exams (with solutions) are posted here, but notice that the number of exams and material covered in them is different in different years.
Course details -- see syllabus Grading: HW-50 pts. The two lowest will be dropped. The quizzes and many of the exam questions are taken from the Home Work. Quiz - 50 pts. The quiz grade will be computed from the average grade. Middle Exams - 100 pts. each: Total 300 pts. The final exam will be composed of two parts, an examination of Ch. 18-20 (100 pts) and a separated cumulative part (100 pts). Your final grade will be based on 600 total points. The demarcations in % of 600 pts are given below A >88%, B> 77%, C>60%, D>50% If your percentage grade is within these ranges, you are guaranteed the associated letter grade. At the end of the course the instructors may adjust these cut offs slightly but only downwards.
Basic concepts: 1. Measurement of a physical parameter 2. Units, systems of units (example: SI) 3. Basic units in mechanics 4. Changing units 5. Significant figures
SI Base Units seven 1) meter (m) distance 2) kilogram (kg) mass 3) second (s) time 4) ampere (A) electric current 5) kelvin (K) temperature 6) mole (mol) amount of stuff 7) candela (cd) intensity of light Derived Unit Measures Derivation Formal Def. hertz (Hz) frequency /s s -1 newton (N) force kg (m/s 2 ) kg m s -2 pascal (Pa) pressure N/m 2 kg m-1 s-2 joule (J) energy N m kg m2 s-2 or work prefix Symbol Factor Giga G 10 9 Mega M 10 6 Kilo k 10 3 Centi c 10 2 Milli m 10 3 Micro µ 10 6 Nano n 10 9 See Appendix A: International System of Units See Appendix D: Conversion Factors Significant figures
Be sure that numerical answers appear with appropriate SI units. Points will be deducted for missing, incorrect, or silly units. If the final answer is in fact a dimentionless quantity, please write the numerical result followed by the word dimensionless
Basic Concepts: Displacement: (SI Unit: m) Average velocity: (SI Unit: m/s) Instantaneous velocity: Average acceleration: (SI Unit: m/s 2 ) Instantaneous acceleration We are dealing with Kinematics
Special Case: Motion with Constant Acceleration
Motion with Constant Acceleration The x(t) versus t plot is a parabola that intercepts the vertical axis at x = x 0. The v(t) versus t plot is a straight line with slope = a and intercept = v 0. The acceleration a is a constant.
Special Case: free-falling body motion Close to the surface of the Earth all objects move toward the center of the Earth with an acceleration whose magnitude is constant and equal to 9.8 m/s 2. We use the symbol g to indicate the acceleration of an object in free fall. a B y A
Kinematics: Taking Advantage of Symmetry
Question A person standing at the edge of a cliff throws one ball straight up and another ball straight down at the same initial speed. Neglecting air resistance, the ball to hit the ground below the cliff with the greater speed is the one initially thrown 1. upward. 2. downward. 3. neither they both hit at the same speed.
In physics we have parameters that can be completely described by a number and are known as scalars. Temperature and mass are such parameters. Other physical parameters require additional information about direction and are known as vectors. Examples of vectors are displacement, velocity, and acceleration. In this chapter we learn the basic mathematical language to describe vectors. In particular we will learn the following: Geometric vector addition and subtraction Resolving a vector into its components The notion of a unit vector Addition and subtraction vectors by components Multiplication of a vector by a scalar The scalar (dot) product of two vectors The vector (cross) product of two vectors
An example of a vector is the displacement vector, which describes the change in position of an object as it moves from point A to point B. This is represented by an arrow that points from point A to point B. The length of the arrow is proportional to the displacement magnitude. The direction of the arrow indicated the displacement direction. The three arrows from A to B, from A' to B', and from A'' to B'', have the same magnitude and direction. A vector can be shifted without changing its value if its length and direction are not changed. In books vectors are written in two ways: Method 1: (using an arrow above) Method 2: a (using boldface print) The magnitude of the vector is indicated by italic print: a.
(3-3) Geometric Vector Addition
Geometric Vector Subtraction Note: We can add and subtract vectors using the method of components. For many applications this is a more convenient method.
Resolving a vector into its components C A B
Unit Vectors A unit vector is defined as a vector that has magnitude equal to 1 and points in a particular direction. A unit vector is defined as a vector that has magnitude equal to 1 and points in a particular direction. Unit vectors lack units and their sole purpose is to point in a particular direction. The unit vectors along the x, y, and z axes are labeled ˆi, ˆj, and kˆ, respectively. Unit vectors are used to express other vectors For example vector a can be written as a = a ˆi + a ˆj. x y The quantities a ˆi and ˆ x a y j are called the vector co mpo nents of vector a.
y Adding Vectors by Components O x
y Subtracting Vectors by Components x O
Which of the following are right-handed coordinate systems?
Chapter 4: Motion in 2 and 3 Dimensions 1-D vectors 2- and 3-D vectors for position, velocity, and acceleration r = r xˆ i + r y ˆ j + r ˆ z k v = d r dt = v xˆ i + v y ˆ j + v ˆ z k a = d v dt = a xˆ i + a y ˆ j + a ˆ z k Decouple motion into components
2-D with CONSTANT ACCELERATION (a x =C, and a y =C ) The x and y motions are decoupled: this means that we can consider both directions of motion independently. x direction motion y direction motion v x = v ox + a x t x = 1 2 ( v + v x ox)t x = v ox t + 1 2 a x t 2 v 2 x = v 2 ox + 2a x x v y = v oy + a y t y = 1 2 ( v + v y oy)t y = v oy t + 1 2 a yt 2 v 2 y = v 2 oy + 2a y y Δ r = Δxî + Δyĵ v = v x î + v y ĵ a = a x î + a y ĵ
Projectile Motion Toss something in the air: a x = 0 and a y = -g x direction motion y direction motion v x = v ox + a x t v y = v oy + gt a y t x = v 1 ( v 2 x t x + v o x)t y = 1 2 ( v y + v o oyy )t x = v + 1 a 2 xt 2 ox t v 2 2 x = v ox + 2a x x y = v + a yt 2 oy t 1 gt 2 2 v 2 y = v 2 oy + 2gy 2a y y