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Physics 111-01: General Physics, Part 1

That’s how we roll.

Agenda

•  Today: Syllabus overview, homework registration, administrative stuff

•  Wednesday: Units, sig figs, measurement •  Reading for Friday: Chapter 1

About Me

•  My office is in Science 356 •  Come say hello! •  Best place to ask questions (besides

during class) is office hours – Tuesdays 11AM-3PM, MW 2-3PM, Thursdays

by appointment •  Best way to contact me is email

–  jfielder@sfsu.edu – put “Phys 111” in the subject line

Administrative Stuff •  Enrollment

– Wait List – Prerequisites – Lab (Physics 112) must be taken concurrently

•  Textbook & Mastering Physics – Course ID: fielder29894 – 2-week free trial period –  Introductory assignment due on Friday!

Register before Feb. 8th or you will be dropped from the class.

Etext, access code, free trial period for Mastering Physics

http://www.physics.sfsu.edu/~jfielder/Phys111S16.html

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Goals For This Class

Help you develop: •  A thorough understanding of the central

concepts of physics •  The ability to solve complex problems

using physics concepts, algebra, and trigonometry

Participation

•  10% of your final grade is class participation – Short writing assignments – Group activities – Voting

•  If you miss class, you cannot make up the participation credit for that day. 15 (about 1/week) are collected, need 10. Make class attendance a firm priority.

Homework •  2 assignments per chapter: one on reading,

one problem set •  Problems from textbook & conceptual

questions •  Working in groups is definitely encouraged,

but the work you turn in must be your own. •  Homework is 20% of your final grade •  HOMEWORK IS PRACTICE FOR EXAMS

Exams

•  3 midterms (20% each) and a comprehensive final (30%)

•  multiple choice and some short problems •  Lowest of the midterm exams is dropped •  Exam dates are not flexible

•  DO NOT MISS EXAMS! THERE ARE NO MAKEUPS!

Grades

•  Homework 20% •  Participation 10% •  Midterms (best 2 x 20% each) 40% •  Final Exam 30%

I do not offer extra credit, but exams and overall grades may be curved. If you need to talk about your grade in detail, let me know.

Syllabus Questions?

Bring signed Student Contract (last page of syllabus) to class

on Monday.

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Agenda

•  Today: Chapter 1 (Sig Figs & Dimensions) •  Intro to Mastering assignment due Monday

(register now!) •  Reading for Friday: Chapter 2 (can start

CH 2 reading assignment on Mastering) •  Walker text is on reserve in the library

under Phys 111

If a bowling ball and a baseball are both dropped from the same height at the same time, which one will reach

the ground first?

A.  The bowling ball, because it has more mass B.  The baseball, because it has less mass C.  The bowling ball, because it is larger in size D.  They will reach the ground at about the

same time E.  None of the above

The Montillation of Traxoline

It is very important that you learn about traxoline. Traxoline is a new form of zionter. It is montilled

in Ceristanna. The Ceristannians gristerlate large amounts of fevon and then brachter it to quasel traxoline. Traxoline may well be one of our most

lukized snezlaus in the future because of our zionter lescelidge.

(attributed to the insight of Judy Lanier)

The Montillation of Traxoline It is very important that you learn about traxoline. Traxoline is a new form of zionter. It is montilled in Ceristanna. The Ceristannians gristerlate large amounts of fevon and then brachter it to quasel traxoline. Traxoline may well be one of our most lukized snezlaus in the future because of our zionter lescelidge.

Directions: Answer the following questions in complete sentences. Be sure to use your best handwriting. 1. What is traxoline?

2. Where is traxoline montilled?

3. How is traxoline quaselled?

4. Why is it important to know about traxoline?

A Commonly Held Incorrect Model of a Student’s Conceptual Framework

tabla rasa

A Commonly Held Incorrect Model of Teaching and Learning

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Physics can be BIG! SI Units: The Système International or “mks”

•  Length: meter (m) •  Mass: kilogram (kg) •  Time: second (s) •  Force: newton (N) •  Energy: joule (J) •  Current: ampere (A) •  Temperature: kelvin (K)

Metric System (Units of Length) •  Everything is based on the meter (m)

– 1 kilometer (km) = 1000 m = 103 m – 1 centimeter (cm) = 0.01 m = 10-2 m – 1 millimeter (mm) = 0.001 m = 10-3 m – 1 nanometer (nm) = 0.000000001 m = 10-9 m

•  Good estimates: – 1 meter is about 3.3 feet – 1 inch is 2.54 centimeters (exact definition!) – 5 miles is about 8 kilometers

Why unit conversions are important!

Units & Conversions

•  Example: How many seconds are in a year?

Scientific Notation & Significant Figures

•  How precisely do we know a number? How many significant figures?

•  All non-zero digits are significant •  Zeros are significant when

–  between other non-zero digits –  after the decimal point and another significant figure –  can be clarified by using scientific notation

•  Example: How many days are there in a year?

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Dimensional Analysis

•  It is often helpful to approach a problem by looking at the units involved

•  Dimensions (such as length) can be expressed in many different units (centimeters, miles, microns, etc.)

•  Example: how could we figure out the speed of an object? What would we need to know?

Quantities in Motion

•  Any motion involves three concepts – Displacement (x, m) – Velocity (v, m/s) – Acceleration (a, m/s2)

•  These concepts can be used to study objects in motion

Motion Basics

•  How objects move through space and time •  Position: location in a coordinate system •  Displacement: change in position

Δx = xf - xi •  Velocity: rate of change in position

v = Δx / Δt •  Displacement & velocity are vector

quantities: include a direction!

Vector Basics •  Vectors are drawn as arrows in diagrams •  A vector quantity is written either in bold or

with a small arrow over the top: v or v •  Ways to express vectors depend on the

coordinate system – Magnitude and angle: angle measured

counterclockwise from x-axis – Components: along x- & y-axes – SOH CAH TOA: Use it, know it, it is your best

friend for decomposing vectors!

Example: A person runs northwest (exactly halfway between due north and due west) at a speed of 2 m/s

1.  Define coordinate system and origin 2.  Magnitude/angle version 3.  Components version

A bird flies 3.0 m due west and then 2.0 m due north. What is

the magnitude of the bird’s displacement?

A.  2.0 m B.  3.0 m C. 3.6 m D. 5.0 m E.  6.0 m

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Displacement Isn’t Distance

•  The displacement of an object is not the same as the distance it travels – Example: Throw a ball straight up and

then catch it at the same point you released it • The distance is twice the height • The displacement is zero

Distance & Displacement Lecture-Tutorial

•  Work with a partner or two •  Read directions and answer all questions

carefully. Take time to understand it now! •  Come to a consensus answer you all agree

on before moving on to the next question. •  If you get stuck, ask another group for help. •  If you get really stuck, raise your hand and I

will come around.