Department of Physics and Applied Physics , F2009, Lecture 1 Welcome to Physics I !!! Prof. Wasserman LECTURE 1

Department of Physics and Applied Physics , F2009, Lecture 1 Outline Why Physics? Course organization Course grading Chapter 1 –Significant figures –Units –Estimating

Department of Physics and Applied Physics , F2009, Lecture 1 Why Physics? Students in this course come from diverse backgrounds and are heading in diverse directions Physics provides all with a scientific toolbox –Physics describes the fundamental operation of the world around us: Engineering, Chemistry, Biology, Astronomy, etc. –Teaches us how to approach complex problems Science is inherently progressive –If approached correctly, we can all contribute! What you are going to do matters!

Department of Physics and Applied Physics , F2009, Lecture 1 Physicists look at the world differently This class will attempt to show you how we understand the world around us

Department of Physics and Applied Physics , F2009, Lecture 1 Course Organization Everything you need to know about the course can be found on the course website:

Department of Physics and Applied Physics , F2009, Lecture 1 Course Organization Physics I meets 4 times a week –Lectures 2:30-3:20 MW, OH 150 –Recitation Sections Varying times, locations Know your instructor and section number –Homework review sessions 6:30-9:30 pm, OH 218 Held every week before HW is due Textbook: Giancoli: Physics for Scientists and Engineers, 4 th Ed. NO LAB THIS WEEK!! RECITATION SECTIONS THIS WEEK!!

Department of Physics and Applied Physics , F2009, Lecture 1 Lectures NO COMPUTERS IN LECTURE!! NO CELL PHONES!!

Department of Physics and Applied Physics , F2009, Lecture 1 Course Grading ItemPoints Standard HW90 LP HW30 Quizzes90 Participation30 Exam 1100 Exam 2100 Exam 3100 Final Exam200 Total750 RangeGrade >600A B+/A B C+/B C D+/C D <265F

Department of Physics and Applied Physics , F2009, Lecture 1 PRS Clickers For detailed info on setting up PRS clickers, go to: You must have your own clicker!! –You cannot borrow a friend’s clicker for class –You may not have more than 1 clicker in class: this is academic fraud. Clickers will be used to determine part of participation grade

Department of Physics and Applied Physics , F2009, Lecture 1 PRS Example Turn on clickers Enter class letter (or number): then “enter” Question: In order to do well in Physics I, you should spend how many hours working on Physics I material for every hour in class (recitation and lecture)? –A) 0-1 HRS –B) 1-2 HRS –C) 2-3 HRS –D) 3-4 HRS –E) 4+ HRS

Department of Physics and Applied Physics , F2009, Lecture 1 Standard Homeworks Homework assignments online at course website ( Due in Recitation Section, returned within ~1 week Graded out of 10, total 90/750 of your final grade Late homeworks not accepted (unless recitation instructor gives OK) Homework review sessions for EVERY homework set. OK to work in groups, but must turn in your own HW and do every problem!!

Department of Physics and Applied Physics , F2009, Lecture 1 Lecture Prep Homeworks These homeworks are designed as review of the previous lecture, and are due before each lecture. Usually consist of 1-2 tutorials, and 1-2 problems Count for 30 pts over the course of the semester DONE ONLINE!!!! –Course “WASSERMANF09”

Department of Physics and Applied Physics , F2009, Lecture 1

Department of Physics and Applied Physics , F2009, Lecture 1

Department of Physics and Applied Physics , F2009, Lecture 1 Quizzes Given by recitation instructor, during recitation. 90/750 of Final Grade. No remakes. (for excused absences, recitation instructor can drop missed quiz). Normalized to class quiz average (a tough recitation instructor doesn’t hurt your final grade!) Should cover material from previous week’s class/recitation.

Department of Physics and Applied Physics , F2009, Lecture 1 EXAMS 3 Mid-Term Exams –Each worth 100 pts. –Taken in class. –Each covers lectures from previous exam up to exam date –No rescheduling –Extra time available for students with disabilities (must have note from Office of Student Disabilities) Final Exam –200 pts. –Date/Time/Location To Be Announced

Department of Physics and Applied Physics , F2009, Lecture 1 Extra Help Need to get help as soon as you feel like you may be falling behind! The first person to contact if you are having problems with Physics I is your recitation instructor!! Recitation Instructors will have office hours each week during which they can meet. HW review sessions UML tutoring center: information on course website (

Department of Physics and Applied Physics , F2009, Lecture 1 Fun ≠ Easy We have worked very hard to make this course fun and interesting! But this does not mean the course will be easy. This stuff matters!! 1hr in class = 4hrs outside of class You will have to work hard to do well in Physics I. You will have to be organized to do well in Physics I. You will have to come to class to do well in Physcis I.

Department of Physics and Applied Physics , F2009, Lecture 1 Physics I (95.141) Lecture 0: Online Basic Trig., Calc. and other mathematical concepts. Lecture 1: Chapter 1

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-3: Measurement and Uncertainty No measurement is perfectly precise –For any measurement, it is important to give the uncertainty in the measurement Either in absolute numbers: 0.1g or 0.2mm, for example Or in percentage: 10m +/- 2%, or 3.2kg +/- 10%

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-3: Measurement and Uncertainty If uncertainty is not explicitly mentioned, we assume it to be 1, or a few units in the last digit specified –“The speed of the car was 51.2 mph” Means… –“The speed of the car was 51.2 mph +/- ~0.1mph”

Department of Physics and Applied Physics , F2009, Lecture 1 Significant Figures Significant figures: the number of reliably known digits in a number –45.21 kg  4 significant figures – m  3 significant figures If you are making a measurement, be careful about how many digits you use!! –i.e. I am 6 ft inches Scientific Notation –4,560,000,000  4.56 x 10 9

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-4: Units Units are important!!! If I am bragging about my weight: –“I weigh 150!” Could mean: –“I weigh 150lbs” Or…. –“I weigh 150kgs” In Physics we try to use the same set of units: SI: Système Internationale

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-4: SI Units Length: meters [m] Time: seconds [s] Mass: kilogram [kg] Temperature [K] For dealing with very small or very large numbers, we can make use of prefixes: G  giga  10 9 M  mega  10 6 K  kilo  10 3 m  milli  µ  micro  n  nano  ,000m can also be written as 100 kilometers (km) s could be written as 100 microseconds (µs)

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-4: Converting Units Sometimes we don’t get problems in the units we like… –Two cars are traveling on the highway, car 1 at 55mph, car 2 travels 200m in 10s. Which is going faster? –Need to convert between mph and m/s  conversion factor –Car 1 –Car 2

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-6: Estimating Why is estimating important?

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-6: Estimating Being able to make order of magnitude estimates is an important skill!!

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-6: Estimating (Fermi Problems) What is the capacity of this room? Could try to count every chair Or could make a quick estimate…

Department of Physics and Applied Physics , F2009, Lecture 1 How many barbers/salons should a town of 300,000 people have? Chapter 1-6: Estimating (Fermi Problems)

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-7: Dimensional Analysis Dimensions of a quantity refer to the units that make it up –Speed  L/T, i.e. [m/s] –Acceleration  L/T 2, i.e. [m/s 2 ] We can learn a lot simply by looking at the units involved in an expression. If someone tells you that the speed of a car is given by the following expression:

Department of Physics and Applied Physics , F2009, Lecture 1 Chapter 1-7: Dimensional Analysis Later in the semester, we will learn that Force has the units of Newtons [N] F=ma F g =GM 1 M 2 /R 2 What are the Units of G-Universal Gravitational Constant?