Dr. Soeren Prell A417 Zaffarano Hall 294-3853 prell@iastate.edu Office Hours: by appointment (just send me a brief email)
Today s Topics: Course structure Mathematical Concepts (Giancoli 1:1-8) Units and Unit Conversions Dimensional Analysis Significant figures Conversions
About myself Dr. Soeren Prell Office: A417 Zaffarano Phone: 294-3853 E-mail: prell@iastate.edu Office hours: by appointment Courses taught at ISU (since 2002) Introduction to Classical Physics I + II Modern Physics Lab Quantum Mechanics I + II General Physics I Research Experimental elementary particle physics at the Large Hadron Collider (LHC) Hobby Judo coach at Cyclone Martial Arts Club
The Physics 111 Team Lecturers: Dr. Soeren Prell Lab supervisor Dr. Paula Herrera Course secretary Deb Schmidt Recitation and Lab Teaching Assistants: Anatoli Frishman, Andrew Goenner, Mengyao Huang, Shreeram Jawadekar, Kyungchan Lee, Soham Pal, Cory Schrandt
Canvas and Course Web Site Canvas Announcements Grades Link to Phys 111 Course Web Page (for back-up, if Canvas does not cooperate) courses.physics.iastate.edu/phys111/homepage.htm Posted material Syllabus Lecture notes HW, quiz and worksheet solutions Exam locations and schedule Exams and solutions, old exam archive Etc.
The syllabus Linked from Canvas and from Phys 111 course web page (under Course Info) http://course.physastro.iastate.edu/phys111/ Lecturer contact information Info on textbook and other course material Incl. for online homework Course schedule Lectures, recitations, hw assignment due dates (online hw and reading), quizzes, exams, etc. Grading policy First homework assignment: read the syllabus carefully!
Exams 3 mid-semester exams Evening exams at Tuesday, February 6 Tuesday, March 6 Tuesday, April 10 8:15 pm 9:45 pm 8:15 pm 9:45 pm 8:15 pm 9:45 pm Final exam Make no other plans for these evenings! May 1 5 day and time TBA, 120 minutes
Recitations Each Friday (50 minutes) Worksheet (40 minutes) Hands-on, interactive learning Quiz (10 minutes)
Labs Read detailed lab info on Canvas under PHYS 111 LABS (Spring 2017) 14 two-hour labs Each section meets every week Prelab must be completed before corresponding lab Check lab schedule for dates & time of your session For any questions regarding labs, e-mail Dr. Paula Herrera (siklody@iastate.edu). Questions based on material covered in recitations and labs will be on the exams!
Student Assistance Physics 111 help room (= TA office hours) Room 53 Physics Lecturer office hours Physics 111 course web site and info on Canvas SI session for Physics 111
How to succeed in Physics 111 Physics can only be learned by doing it (just like swimming or juggling) Lectures Prepare for lecture Read the indicated assignments before class Attend classes actively Ask questions, participate in interactive problems Homework and worksheets Do all problems Review the solutions Understand concepts and learn from your mistakes Don t fall behind!
Lectures Turn off your and put away your cell phone Laptops are discouraged in lecture No need to bring your textbook Note taking encouraged Lecture notes will be posted on the course web page after each lecture Occasionally, there will be a short quiz in class for extra credit (You get half the possible points just for taking the quiz.)
Questions?????
Lecture 1 Scientific method, units, dimensional analysis, significant figures
How Physics works (the Scientific Method) Observe and measure Build a model check Make a prediction
Units Fundamental quantities Length or distance [L], time [t] and mass [m] + others to be named at a later date. Derived quantities Combinations of the above quantities e.g. speed or velocity are specified in terms of [L]/[t]
But since there are several systems, you may need to convert between units Some common unit conversions 1 ft = 0.3048 m 1 mi = 1,609 m 1 hr = 3600 sec 1 day = 24 hrs For example, given that 1 m = 3.28084 ft, this 8611-m mountain is 28251 feet high. More unit conversions are listed on the backside of Giancoli s cover page The only countries not using the metric system are the US, Liberia and Myanmar.
Example When my son was born, he measured 21 inches long. What is this value in centimeters? 53 cm 1 inch = 2.54 cm How many meters? So, (21 inch) x 2.54 cm = 53.34 cm 1 inch 1 m = 100 cm So, 53.34 cm x 1 m = 0.5334 m 100 cm Conversion Factors 0.53 m Anyone have any problem with my answers? Precision!... Significant digits. Least precise quantity determines precision.
Problem solving strategies 1) In all calculations, write down the units explicitly.
Dimensional Analysis Dimension physical nature of a quantity and the type of unit used to specify it. Length [L], time [t] and mass [m] Velocity, speed (v): [L]/[t] e.g. meters/sec. Acceleration (a): [L]/[t] 2 e.g. meters/sec. 2 Force (F) : [m][l]/[t] 2 e.g. kg-meters/sec. 2 1) Dimensions on both sides of = must be consistent 2) Only quantities with same dimension can be added or subtracted
Are the following equations dimensionally correct? x = 1 vt 2 2 x = 1 at 2 2 élù ê t ú ë û [ L] = [ t] 2 = [ L][ t] é L ê ët ù ú û [ ] [ ] 2 L = t [ L] 2 =
Problem solving strategies 1) In all calculations, write down the units explicitly. 2) If you carry your units along you can check whether the dimensions are correct and consistent
Trigonometry sinq = h o h q = sin -1 h o h cosq = h a h q = cos -1 h a h tanq = h h o a q = tan -1 h h o a Pythagorean theorem: 2 2 2 h = h + h o a
Example The gondola ski lift at Keystone, Colorado is 2830 m long. On average, the ski lift rises 14.6 above the horizontal. How high is the top of the ski lift relative to the base? θ h H sin θ = H/h H = h sin θ = (2830 m) sin 14.6 = 713 m
Problem solving strategies 1) In all calculations, write down the units explicitly. 2) If you carry your units along.. You can check whether the dimensions are correct and consistent 3) Draw a figure and label it regardless of how simple the problem may appear! Most times you will have to determine relationships between variables. Visualization makes all the difference!
A tougher one How tall is the antenna itself? H b H a 35.0 85.0 m 38.0 85.0 m (a) (b) H a ( ) H ( ) = 85.0 m tan 35.0 and = 85.0 m tan 38.0 b ( ) ( ) Hb - Ha = 85.0 m tan 38.0-85.0 m tan 35.0 = 6.9 m
Problem solving strategies 1) In all calculations, write down the units explicitly. 2) If you carry your units along.. You can check whether the dimensions are correct and consistent 3) Draw a figure and label it regardless of how simple the problem may appear! Most times you will have to determine relationships between variables. Visualization makes all the difference! 4) Even with all of the formulas in front of you, there is (almost) always a critical relationship or condition that you must satisfy.think before you solve!
Required MATH Algebra (esp. solving 2 equations with 2 unknowns) Trigonometry Exponentials and logarithms No calculus We will visit (or revisit) vectors in the 4 th lecture.
ACT: Algebra A = BC/(D+E) 1. E = BC/A + D 2. E = BC/A D 3. E = BC/AD
SIGNIFICANT FIGURES For calculations involving more than one parameter, the number of significant figures is determined by the least precise parameter ex. x = 6.23 m t = 2.3 s v = x / t = 2.7087 m/s 2.7 m/s
ACT: Significant figures v = x / t = 5.358 m / 2.01 s = 2.66567 m/s 1. v = 2.66 m/s 2. v = 2.67 m/s 3. v = 2.665 m/s 4. v = 2.666 m/s
SCIENTIFIC NOTATION ex. A = 35,000,000 = 3.5 x 10 7 ex. B = 0.0000035 = 3.5 x 10-6
ACT: Scientific notation B = 0.00021 1. B = 2.1 x 10-2 2. B = 2.1 x 10-3 3. B = 2.1 x 10-4 4. B = 2.1 x 10-5
Standard prefixes for the decimal system These are the standard SI prefixes for indicating powers of 10. Many are familiar; Y, Z, E, h, da, a, z, and y are rarely used.