Download Welcome to PHYSICS 149 - Purdue Physics

Welcome to PHYSICS 149
Mechanics, Heat and Wave Motion
Prof. Norbert Neumeister
http://www.physics.purdue.edu/phys149
Lecture 1
• Course Introduction
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Philosophy
Policies
Requirements
Administration
• Chapter 1
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Lecture 1
1.1 Why study physics?
1.2 Talking physics
1.3 The use of mathematics
1.4 Scientific notation and significant figures
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Course Format
• Lectures:
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Time: Monday, Wednesday 10:30 – 11:20
Lecture Room: PHYS 203
Instructor: Prof. N. Neumeister
Office hours: by appointment
Office: PHYS 374 Phone: 49-45198 Email: [email protected]
(please use subject: PHYS 149)
• Recitations:
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Time: Friday 10:30 – 11:20 am (section 1), 11:30 – 12:20 am (section 2)
Lecture Room: PHYS 201
Teaching Assistant: Andrew Kramer
Office hours: by appointment
Office: PHYS 198 Phone: 49-45534 Email: [email protected]
• Homework:
– CHIP coordinator: Dr. V.K. Saxena, Office: PHYS 176
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Textbook
The textbook is College Physics, Vol I, second
edition, by Giambattista, Richardson,
Richardson (McGraw-Hill). We will cover
almost all of the topics in this volume.
The textbook publisher has also made available a very nice Web
site containing additional questions, solutions, animations, etc.
You can find this at: http://www.mhhe.com/grr/
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Basic Course Philosophy
• Read about it
– Reading assignment
• Untangle it
– Lecture: Mostly concepts
– Interactive Lecture Quiz (ILQ): Participation
• Challenge yourself
– CHIP Homework: Problem solving
– Help Center
• Close the loop
– Recitation: Homework & Quiz Review, Problem solving
– Six recitation quizzes
• Evaluation
– Two midterm exams and one final exam
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Background Needed
• Algebra (high school)
– manipulation of formulas
– solutions of 2 equations with 2 unknowns
– solution of quadratic equation
• Trigonometry
– sine, cosine, tangent
– Pythagorean theorem
• Geometry
– circle, rectangle, triangle
– sphere, cylinder, parallelepiped
• See Appendix A (Mathematics Review) of your textbook if
your math background needs to be refreshed and/or
strengthened.
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Lectures
• Participation is key
– Come to the lectures prepared!
• Not everything you need for exams
– Concepts, Connections, Motivation
– Comprehensive Text
– Problem Solving: Homework + Recitation
• Taking Notes
– Lecture notes can be downloaded from the course web site
– Some key pieces for you to fill in
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Interactive Lecture Quizzes
• We will use iClicker for interactive lecture quizzes
• Can be purchased at the Purdue bookstore
• Registration:
– You must register your iClicker on CHIP
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Use serial number at the back of your iClicker
Go to CHIP  Student Gradebook
DO NOT register on the iClicker web site!
See “Quick Guide to CHIP”
– Deadline: Monday August 31, 2009
• We will start during the second week of class
• Two questions per lecture; one point for attendance
• Will count toward your final grade!
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Recitation
• Developing problem-solving skills
– You need to complete your homework before coming to
the recitation.
– The homework is due Friday at 10:30 am (before
recitation).
– You will have an extra week to complete the first
homework.
• The recitation instructor will administer 6 recitation quizzes
during the semester. This quizzes will contain problems
similar to the one found on the exams.
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Homework
• We will use CHIP (Computerized Homework In
Physics) for homework assignments
• Must complete your homework before the recitation
• Always keep 5 significant figures!
• For due dates see course web site (Calendar)
• Homework is computer graded (CHIP)
– 100% if done before the deadline (Friday 10:30 AM)
– 50% if completed within a week
– 0% after that
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General Information
Room PHYS 144: Undergraduate office
Room PHYS 11: Help center
Room PHYS 290: Physics Library
For questions concerning CHIP contact:
Dr. V.K. Saxena: Office: PHYS 176, Phone: 49575
In case of problems with CHIP click on the Problem Report link on the
course's CHIP web page, or send E-mail to
[email protected] (identify yourself by giving your full
name and Purdue Student ID number).
You will be able to access your grade-book (using CHIP) and check the
latest scores. It is your responsibility to check your score on a regular
basis
You will find more information about accessing and using CHIP on a
separate handout available from room 144.
http://chip.physics.purdue.edu/public/149/fall2009/
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Activities and Responsibilities
• In-class activities and responsibilities
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Coming to lectures, taking notes, asking questions
Participate in the lecture quizzes
You are responsible for attending all classes
If you miss class, it is your responsibility to find out what you missed
• Outside class
– Read and keep up to date with the text
• Read the assigned textbook sections thoughtfully
• Stop and ask yourself if you understand what you just read
– Going to recitation, doing homework on CHIP
– Doing extra problems, old exams
• Work as many problems as you can - more than just the assigned homework
problems
– Getting help when you need it
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Exams and Grades
• Exams:
– There will be two evening exams and a final exam. All exams are
closed-book, but relevant formulas and constants will be provided
where needed. Practice exams are available on the course
website.
– Exam 1: Oct 6, 2008, 18:30 – 19:30, PHYS 112
– Exam 2: Nov 18, 2008, 18:30 – 19:30, PHYS 110, PHYS 223
• Grades:
– The final grade will be determined on the following basis:
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300 points final exam
300 points two evening exams (150 points each)
150 points CHIP homework
150 points recitation quizzes
100 points lecture quizzes
1000 points total
– We will use plus/minus letter grades.
– The exact cut-offs for letter grades will not be determined until the
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What is Physics?
• Fundamental description of
– Matter
– Energy
– Space and Time
• It has many branches:
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Astrophysics
Biophysics
Condensed-matter physics
Cosmology
Geophysics
High energy physics
Nanophysics
Nuclear physics
Optics…
• Relevant to many other fields
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Biology
Engineering
Architecture
Medicine
Music
Chemistry
Art…
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Why Study Physics?
• All natural sciences (and engineering) are built on a
foundation of the laws of physics.
• Physics is important for understanding the technology
around us: Laser, x-ray imaging, MRI, thermometers, etc.
• By studying physics, you acquire skills that are useful in
other disciplines: thinking logically and analytically, solving
skills, and so on.
• Needed to understand to make decisions important for
society:
– Nuclear energy,
– Global warming,
– etc.
• Physics is beautiful!
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Talking Physics
• The language of physics is precise, and sometimes
uses common words in unusual ways. Be alert!
• For example:
– Speed vs. Velocity
– Mass vs. Weight
– Force vs. Power
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The Use of Mathematics
• A physical parameter consists of a number and a
unit. For example:
– Distance: 100 km, 100 m, 100 cm
– Time: 3 years, 3 days, 3 hours, 3 minutes, 3 seconds
• A working knowledge of algebra, geometry, and
trigonometry is essential in the study of physics.
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Factors
• The factor is the ratio of the new value to the
original value. We often say that a quantity is
increased or decreased by some factor.
– Let’s say that the number of students in my class was
100 last year, but I have 200 students this year.
– In this case, factor = 200/100 = 2
– We say that the number of students has increased by a
factor of two.
– Let’s say that the price of a monitor was $400 last year,
but its current price is $200.
– In this case, factor = $200 / $400 = 1/2
– We say that the price has decreased by a factor of two.
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Increasing or Decreasing %
• If a quantity increases n%, the original value is
multiplied by a factor of 1 + (n/100).
– My salary has increased 10%. This means that my new
salary is 1.1 (= 1 + 10/100) times the old salary.
• If a quantity decreases n%, the original value is
multiplied by a factor of 1 – (n/100).
– Gasoline price has decreased 5%. This means that the
new price is 0.95 (= 1 – 5/100) times the old price.
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Proportions
• When we say that A is proportional to B (written
A ∝ B), we mean that if B increases by some
factor, then A must increase by the same factor.
• A ∝ B means A1/A2 = B1/B2 .
– For instance, the circumference (C) of a circle equals
2π times radius (r), that is, C = 2πr.
– Then, we say that C is proportional to r
(or C ∝ r).
– If r doubles, then C also doubles.
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Scientific Notation
• In scientific notation, a number is written as the
product of a number between 1 and 10 and a whole
number (integer) power of ten.
– The radius of Earth is 6,380,000 m at the equator.
It can be written 6.38 × 106 m.
– The radius of a hydrogen atom is 0.000 000 000 053 m.
It can be written 5.3 × 10-11 m.
• The integer power (of ten) is useful for comparison.
– We can say that the radius of Earth is 1017 (= 106 / 10-11)
times larger than the radius of a hydrogen atom
approximately.
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Scientific Notation
• Physics can describe phenomena:
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Spiral galaxies: 1019 m
Sun d=109 m
Earth d=107 m
Atoms =10-10 m
Nucleus =10-14 m
Proton =10-15 m
Quarks<10-18 m
• The power of ten http://micro.magnet.fsu.edu/primer/java/
scienceopticsu/powersof10/index.htm
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Significant Figures
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Significant figures indicate the “precision” of a quantity or a measurement.
– 12 g is not the same as 12.0 g in terms of precision.
– 12 g implies a value more than 11 and less than 13, while 12.0 g tells you that the value
is between 11.9 and 12.1.
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Nonzero digits are always significant.
– 1.23, 12.3, and 123; all have 3 significant figures.
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Final or ending zeros written to the right of the decimal point are significant.
– 12.00 has 4 significant figures.
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Zeros written to the right of the decimal point for the purpose of spacing the
decimal point are not significant.
– 0.001200 has 4 significant figures (the first three zeros are NOT significant figures).
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One or more zeros written to the immediate left of the decimal point are
ambiguous; they may or may not be significant. (Rewriting the number in scientific
notation is one way to remove the ambiguity.)
– 9500 has 2 to 4 significant figures. On the other hand, 9.500 × 103 m, 9.50 × 103 m, and
9.5 × 103 m have 4, 3, 2 significant figures, respectively.
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Zeros written between significant figures are significant.
Lecture
– 11.001200 has 7 significant Purdue
figures.University, Physics 149
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ILQ 1-1 (unofficial)
State the number of significant figures in
0.005800 cm:
a) 7
b) 4
c) 5
d) 2
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ILQ 1-2 (unofficial)
Rewrite 0.005800 cm in standard scientific notation:
a) 5.800×10-3 cm
b) 5.8×10-3 cm
c) 0.58×10-2 cm
d) 0.5800×10-2 cm
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Prefixes (the Power of 10)
• The value of a quantity can be too large or too small in a
unit. It is very convenient to use a prefix in front of the unit.
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peta
tera
giga
Mega
kilo
deci
Centi
Milli
Micro
Nano
Pico
Femto
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G
M
K
d
c
m
µ
n
p
f
1015
1012
109
106
103
10-1
10-2
10-3
10-6
10-9
10-12
10-15
•The radius of Earth is
6,380,000 m at the equator. It
can be written 6.38 × 106 m or
6.38 Mm.
•The radius of a hydrogen
atom is 0.000 000 000 053 m.
It can be written 5.3 ×10-11 m
or 0.53 pm.
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Equations
• Understand the concepts first!
• Equations allow us to use the concepts to make predictions
quantitatively.
• Physicists perform experiments to verify predictions.
• Units are an essential part of each value in equations and
must be handled using dimensional analysis techniques
• Vector equations relate direction as well as magnitude. You
will learn about vectors in this course.
– The car moved 2 miles
– The car moved 2 miles west provides more information
West
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