8/26/2019
General Physics: Mechanics
PHYS 211
Today’s Material: Administration; Units
Fall 2019
Penn State; University Park
Dr. Daniel Costantino
Office Hours:
123 Osmond; Tu 10AM – noon; Th 1PM – 5PM
most other times (drop by or e-mail)
Dr. C or similar is fine for addressing me
djc321@psu.edu (use your PSU e-mail address)
Welcome to Physics
• Why take physics?
– Studies everything
– Generate theoretical models to analyze reality
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What’s going on in PHYS 211?
_________ Motion of Objects
Details in
“Learning Objectives”
in Canvas
Kinematics
________ Motion of Objects
Dynamics
(forces)
Energy
Momentum
Rotational Versions
__________ of Types of Interactions
Oscillations
Gravity
Course Info is at Canvas
https://canvas.psu.edu/
PHYS 211: Mechanics (UP; Fall 2019)
Syllabus is there (all policies will be followed)
Class notes are posted so you don’t have to write everything
My suggestion: print out and add notes during class
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Grade Calculation
Class Segment
Weight
Class Participation (CP)
3%
Quizzes (Q)
2%
Recitation Activities (Rec)
10%
Lab Activities (Lab)
10%
Pre-Class Activities (PC)
2%
Homework (HW)
8%
Midterm 1 (MT1)
15%
Midterm 2 (MT2)
15%
Midterm 3 (MT3)
15%
Final Exam (FNL)
20%
Extra Credit (EC)
2%
(Course Grade) = 0.03 × CP + 0.02 × Q + 0.10 × (Rec + Lab) + 0.02 × PC + 0.08 × HW + 0.15 × (MT1% + MT2% + MT3%) + 0.20 × FNL% + EC
Course Materials
Physics for Scientists and Engineers: A Strategic Approach with Modern Physics
Knight (Fourth Edition / Revised Custom Edition for Penn
State)
Modified Mastering for Physics 211
________day trial period available
come bundled together at bookstore
i>clicker
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Approaching the Material
Non-ideal approach:
I just want to get a *insert grade*
often yields disappointing results
Suggested approach:
I want to understand the material
exams test understanding so…
to work on understanding…
Practice & You
minimize passive time
when reading text (suggestions in Canvas)
answer “Stop to Think” questions
look at “Questions”
in addition to assigned homework:
Pre-Class Assignments:
short Assignments on
__________ material
work on interesting looking “Problems”
in class (119 Osmond, lab, & recitation)
Clicker Questions
participation questions throughout
these help me gauge your progress and adjust class
earn up to 1 point per day
more opportunities to earn than necessary for full score
must attend correct 211 section to earn any
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Clicker Check
When you get to class in 119 Osmond, follow the directions on the back of
your clicker to set its frequency to AD.
Did you do that?
A. Yes and the green light went on.
B. I thought I did, but the green light isn’t going on.
C. I decided against it.
D. A red light keeps blinking.
Recitation & Lab
Work on detailed problems
Get hands on observations
main problem solving experience next to homework
work in groups of up to 3 students
time and room determined by your 211 section
attend the ________ section (or you won’t get a grade)
In the event of an unavoidable absence:
if possible, speak with me beforehand or the week of the absence
otherwise complete the makeup request form in Canvas
and attend your makeup
see syllabus for details
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Homework System
All homework and pre-class assignments are online
http://www.pearsonmylabandmastering.com/northamerica/
Course ID: costantino22549
Benefits of online homework include:
instructors can spend more time helping rather than grading
Grading is done by a computer
Need to be within 1% of theoretical value
(use three significant digits unless instructed otherwise)
My Suggestion: work with variables;
wait to plug in numbers as last step
Must complete each part
Must use correct
symbols:  vs. u
to get credit for a problem
Need correct ID; use your Penn State e-mail address
Typical Schedule
Week 1
________: pre-class assignment due at midnight
Monday & Wednesday: discuss material in 119 Osmond
Week 2
Monday: discuss material in 119 Osmond
Monday – Thursday: Look at material in Lab & Rec
____________: homework due at midnight
Intro to System: 8/29
First Graded Assignment: 9/3
Don’t wait until last minute to work on activity
You get multiple attempts on most problems
Check with me or a TA (or a peer) if you are encountering trouble
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Exams
all Multiple Choice Questions
Midterm Exams
20 Questions Each
Thursday 9/19 (8:00PM – 9:15PM)
Thursday 10/17 (8:00PM – 9:15PM)
Thursday 11/14 (8:00PM – 9:15PM)
Have a class then?
Request a Conflict (link in Canvas)
Final Exam
25 Questions
Sometime Monday 12/16 – Friday 12/20
Request a Conflict (in LionPATH) 9/23 – 10/13
Sheet of Formulae & Constants will be provided on each exam
practice to prepare for time constraint
Concept Quizzes
Taken in Pollock Testing Center
Pre-Quiz
let’s me know where we stand to start off
_____________ Wednesday (8/27 or 8/28)
you’ll get an e-mail about this later today
1% of final grade for taking
Post-Quiz
last Tuesday or Wednesday of semester (12/10 or 12/11)
1% of final grade for taking
If you take both:
Extra Credit on final grade = 2% × (Post-Quiz Score)
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We’re Here to Help You
My role includes
present material as clearly as I can in class
correct any errors I may make as quickly as possible
My most important role:
help address difficulties in class / in my office / via e-mail / on Piazza
barring emergencies, I will always be in for
TAs
office hours
appointments
assist you in lab and recitation
Recitation TAs hold office hours
You’re Here to Learn
Your role includes
Being prepared to engage in the material
Focusing on task at hand
Looking for assistance if you require it
If you have a question…
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One More Resource
Forum for asking questions about the class
Get answers
from me or
classmates 24/7
Help classmates
and gain more
understanding
Keep all responses appropriate
(PSU Principles, ECoS Code)
Important Dates
•
•
•
•
•
•
Mo 8/26: Class Meets in 119 Osmond; no PHYS 211 lab or recitation
Tu 8/27: no PHYS 211 lab or recitation; possibly take pre-quiz
We 8/28: Class Meets in 119 Osmond and lab and recitation might begin (if your section meets Wednesday)
Th 8/29: Intro assignment for HW and lab and recitation might begin (if your section meets Thursday); GSG begins
Sa 8/31: Regular Drop Ends
Su 9/1: Regular Add Ends (sections now fixed for semester)
•
•
•
•
Mo 9/2: No PHYS 211
Tu 9/3: No PHYS 211 lab or recitation; Pre-Class 01 due; AIP Survey due (linked to in Canvas starting on 8/26, one
of two sources of extra credit)
We 9/4: PHYS 211 meets as scheduled
Th 9/5: HW01 due; PHYS meets as scheduled
•
Th 9/19: Midterm 1
•
Th 10/17: Midterm 2
•
Th 11/14: Midterm 3
•
Fr 11/15: Late Drop Deadline
•
Mo 12/16 – Fr 12/20: Final Exams Week
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Any questions about any of that?
Now, on to the material
Units
Scales used for different quantities
We’ll mainly use SI (Le Système International d'Unités)
Seven __________ which Define Seven Base Units
Constant
PHYS
Quantity
SI Unit
Cs
time
c
length
meter (m)
h
mass
kilogram (kg)
e
k
NA
Kcd
electric current
temperature
English Unit
second (s)
inch, foot, yard, mile
slug, pound-mass
ampere (A)
kelvin (K)
amount
mole (mol)
luminous intensity
candela (cd)
other units are “derived” from base units: e.g. speed: meters per second (m/s)
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When to Include Units
(unless if units are obvious)
Mars Climate Orbiter
Cautionary Tale
http://mars.jpl.nasa.gov/ms
p98/gif/mars-mco-2-t.jpg
Launched: December 11, 1998
Arrived at Mars: September 23,1999
: September 23,1999
$655.2 million dollar for total project
Cause of error: two teams
One group used English units; One group used SI units
Sources: http://mars.jpl.nasa.gov/msp98/orbiter/fact.html, http://mars.jpl.nasa.gov/msp98/news/mco990923.html,
http://mars.jpl.nasa.gov/msp98/news/mco990930.html
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Unit Analysis
A way to check an equation’s units
Look at units of each part of equation
units of length are [L]
units of time are [T]
units of mass are [M]
Derived units for
speed:
[speed]
[L]
=
[T]
If a has units of [L]/[T]2, which of the following gives speed?
at2
at
Units:
Unit Analysis and Checking an Equation
Three basic things to check in an equation:
1) Left and right side have the same units
Like on previous slide
2) Terms getting added/subtracted have the _____ units
What is 5 feet + 1 pound?
3) Arguments of functions
-trig functions’ arguments should be __________________
-exponents should be ____________
What is sin(1 m) or 21 s?
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Unit Conversions
Always involves multiplying by ___
Definition of foot: 1 foot = 0.3048 meters
So:
.
.
1
Writing out conversions formally makes life easier
Converting miles per hour to meters per second:
1 mi = 5280 ft
1 hr = 3600 s
1 mph
1
mi
hr
0.4470 m/s
Summary
• Check Syllabus for Policies
• Always record units!
– Unit analysis can check work
– Write out unit conversions formally to avoid errors
• If you have a question about anything ASK IT
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The following slides are provided for reference and will not
be discussed in class
Reporting Values
Three basic things to consider
1) Appropriate Units (for quantity and size)
my weight: pounds
newborn’s weight: ounces
2) Scientific Notation
3) Significant Digits
In formal use (e.g. HW) don’t use too many or too few
(rules in book)
In casual use, three is often enough (gives answer to 1%)
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Position
Origin sets 0 point
Coordinate axis sets what is positive
x(t) = position at time t
size is in meters
sign gives which side of
origin an object is on
+x
http://en.wikipedia.org/wiki/File:London_2
012_Olympic_100m_final_start.jpg;
Usain Bolt won and set Olympic Record
Picture shows start of 100 m race
x(0 s) =
Usain Bolt ran race in 9.63 s:
x(9.63 s) =
For camera man xcamera(t) is ________
Change of Position
(Change of any quantity) = (____ value) – (____ value)
Displacement is the change of position over a time interval
x = xf – xi
Position at ____
of interval
Position at ____
of interval
1800
Car A
1600
Position (m)
1400
1200
Car B
1000
Which car is faster?
800
600
400
200
0
0
10
20
30
Time (s)
40
50
60
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Average Velocity
Δ
Δ
1800
Car A
1600
1400
Position (m)
Defined as:
Average Velocity
during interval
Displacement
during interval
Car B
1200
1000
800
600
Car C
400
200
Change in
Time of interval
0
0
10
20
30
40
50
60
Time (s)
Velocity = ______ of Change of Position
SI Units: meters per second (m/s)
Average Velocity
1800
Car A
1600
1400
Position (m)
Δ
Δ
Car B
1200
1000
800
600
Car C
400
Average velocity for these
cars from 20 – 40 s:
A
;
1200 m
40 s
600 m
20 s
C
;
200 m
40 s
1000 m
20 s
200
0
0
10
20
30
40
50
60
Time (s)
________ since A moves
to bigger positions
_______ since C moves
to smaller positions
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