Welcome Physics 102 Professor Lee Carkner Lecture 1

Questions to Consider  Am I in the right place?  Physics 102: Principles of Physics  Do I have the right stuff?  James Walker, “Physics”  Lab manual  Calculator  WebAssign card  available at register at Runestone Bookstore

Things to Know  Professor  Dr. Lee Carkner  Office Hours  MWF 10-11am  Science 208  Help session:  TBA  Lab section  See me after class to change

How Does the Class Work?  Read the book material before class  Do the WebAssign homework  Come to class  Do the PAL discussion questions  Lab once a week  Two tests and final

Web Page   Outline gives homework and readings  Lectures posted online before class  Syllabus and WebAssign guide also posted

Grading  Two tests -- 30%  Final -- 25%  Homework -- 15%  PAL -- 10%  Lab -- 20%

WebAssign  Homework will be entered and graded online  At webassign.com  Click on student login  Username is your first and last name together (e.g. “johnsmith”)  Institution is “augustana”  Password is same as last semester  Augustana ID number if new to class  After login, click on the current assignment and complete it  WARNING: Can only submit it twice  If you are new to Webassign read tutorial on class web page

Homework  Homework will generally be from book  Will be posted on webpage  WebAssign will randomize numbers  Available at noon M,W,F  Due at midnight M,W,F  Cannot turn homework in late or make up  Can drop lowest three  Each homework worth same amount (100 points)  15% of grade

PAL  What is PAL?  Physics Active Learning  Each class you will get a PAL worksheet  Contains questions about the material and feedback opportunities  Worth 10% of your grade  Need to come to class  Can drop (or skip) three PAL’s  “Physics is your PAL!” 

Guidelines for Work Handed In  Written answers must be in complete sentences  Numbers must have units  Answers must reasonable  If not reasonable, explain why  All work must be neat and easily readable

Today’s PAL  Please answer the first questions:  What is Physics?  What are my goals in taking Physics?  Feedback:  Please list:  Your major  The highest level of math you have taken (Algebra, geometry, trig, pre-calc, calc)  Comments

Answers  What is Physics?  Phys"ics (?), n. The science of nature, or of natural objects; that branch of science which treats of the laws and properties of matter, and the forces acting upon it; especially, that department of natural science which treats of the causes (as gravitation, heat, light, magnetism, electricity, etc.) that modify the general properties of bodies; natural philosophy. --Webster’s Dictionary 1913

What is Physics?  Physics is a way of figuring out how things work  More specifically: what are the underlying rules that govern how things work?  We will deal mostly with classical physics:  i.e. How did things work before 1900?

Why Take Physics?  You may need to know how things work  You can learn how to:  Use reason and logic  Solve problems  Use mathematics  It is useful to understand how we know how things work

Thermodynamics  What is thermodynamics?  Thermo  Involves temperature  Dynamics  Involves mechanics  Thermodynamics is the study of thermal and mechanical energy  How do you transform one into the other?

Where Does Thermodynamics Come From?  Back in the early 1800’s people figured out that you can transform thermal into mechanical energy  Can make a device that turns heat into work  A heat engine  Problem: sometimes the engine would turn heat into horrible bodily injury  Need to understand what is going on in the engine

What is this Stuff?  Liquid Nitrogen  The liquid form of the nitrogen gas that makes up air  Temperature = 77 Kelvin = -320 F  LN will cause frostburn on contact  What is it doing?  Boiling  Changing phase from liquid to gas

Principles of Thermal Physics  Lets think about the first five key variables in thermodynamics:  Heat  Work  Temperature  Pressure  Volume

The Pringles Launcher: A Simple Heat Engine  For the Pringle’s launcher:  How does the P,V and T of the material inside the can change?  Describe the heat flow  How could you measure the work?

LN and Thermodynamics  Using LN demonstrates how things are affected by temperature changes  The properties of common objects depend on temperature  The surface of the Earth is at a very special temperature (~0 Celsius)  Most of the universe is not  Our common sense about how things works only applies to a little corner of the universe

Low Temperature Physics  How is heat transformed into energy?  Heat will expand a gas which in turn can do work  How does temperature effect molecular bonds  Low T causes bonds to become less flexible