1
Physics 1110: Mechanics • Instructors:
– John P. Cumalat – Daniel Dessau
• Classroom: Duane G1B30 (here) • Text: Fundamentals of Physics 9th
Edition by Halliday & Resnick and Walker
• Announcement: If you are waitlisted, then you need to sign up for one of the open lectures and tutorial section. Recitations start tomorrow.
• Today will cover course logistics. Web page: http://www.colorado.edu/physics/phys1110/phys1110_sp12/
Four Lecture Sections
• Physics 1110-100 9:00- 9:50am G1B30 • Physics 1110-110 9:00- 9:50am G2B21 • Physics 1110-200 11:00-11:50am G1B30 • Physics 1110-210 11:00-11:50am G2B21
Must go to the class where you are registered! If you are waitlisted, then consider one of the
remote video rooms. 2
Huge Enrollment – more than 750 students
3
Instructors
John P. Cumalat Main lecturer
Fields questions related to lectures, exams, administrative issues
Office: F321, 303-492-8604, [email protected]
Office hours: M 1-2 or by appointment
High Energy Experimentalist
Daniel Dessau Tutorial and CAPA homework coordinator
Fields questions related to tutorials, CAPA, exams
Office: F627, 303-492-1607 [email protected]
Office hours: W 1-2 or by appointment
Condensed Matter Experimentalist
4
The web pages contain all sorts of information which will be of use to you.
Changes weekly so check frequently.
Web page: http://www.colorado.edu/physics/phys1110/phys1110_sp12/
Important Dates Jan 19: First day of class Jan 25, 5:00 pm: Deadline to add a course without instructor's signature Feb 1: Deadline to drop a course without instructor's signature Feb 3: Deadline to add a course without petitioning your Dean Feb 16, 7:30-9:00 pm: Exam 1, Location to be announced Feb 29: last day to move final if you have 3 or more same day Feb 29 (if in Engineering): Deadline to drop a course without petitioning your
Dean Mar 15, 7:30-9:00 pm: Exam 2, Location to be announced Mar 23 (if in A&S): Deadline to drop a course without petitioning your Dean Apr 19 , 7:30-9:00 pm: Exam 3, location to be announced Mar 26-30 : Spring break, no classes May 4 : Last day of classes Wed. May 9, 7:30am - 10:00am: Final Exam, Coors Event Center
5
6
Grades • 68% Exams: 3 midterms count 15% each and one
cumulative final counts 23% • 10% Tutorials: 3% tutorial participation, 7%
tutorial homework • 15% CAPA homework • 3% “Smart Physics” prelectures • 4% In-class clicker questions • Also, you can receive extra credit for filling out the
attitudes survey as part of the CAPA homework during the first week
7
Tutorials (10%)
• Tutorial: One hour session on Thursday in G2B75, G2B77, or G2B60, in your assigned room, with groups of four working through workbook questions – credit for participation
• Tutorial homework: Long answer questions due in the following week tutorial – credit for good answers
Goal: An in depth examination of an important concept
8
Traditional homework (CAPA) (15%) • Homework will be due most weeks (except for
this week and exam weeks) at 10pm on Friday. • This week the homework will be due next
Tuesday at 10pm • Paper copies of your questions with your CAPA
PIN number are in Duane G2B hallway below the lecture hall. Available after 5pm on Friday the week before the due date
• Answers can be entered into any computer with internet access and a compatible browser
• You generally have 5 tries per problem
Smart Physics Prelectures (3%) • Prior to most lectures you will be required to
view an on-line pre-lectures. • 2/3 points from viewing material • 1/3 points from completing “checkpoints” • Log into www.smartphysics.com • Click Register – follow syllabus guidelines Class Name is `Phys1110_Sp12’ Access Key is `Newton’
9
www.smartphysics.comwww.smartphysics.com
smartPhysicsincludes:1. OnlinePreLectures(animatedlessons,completed
beforelecture)
2. OnlineCheckPoints(quizzestocheckknowledge,completedbeforelecture)
3. Lectures(interacEve,withclickeracEviEes)
smartPhysicsandCourseOverview
11
• iClickers are required: can purchase at bookstore – You should label yours in case of loss or mixup
• When a physics question is asked, discuss with a “study group” of a few people in your vicinity
• Then, everyone in the group should vote the same • If you disagree you should try to explain to the
group why you think your answer is correct • The group discussion is required!
Classroom response system (clickers)
12
• Register at http://oit.colorado.edu/node/779
• Receive 2 points for an answer plus a point for the correct answer.
• Score keeping starts 1/23/2012 • Lowest five scores are dropped • Why do we use clickers?
– Breaks up lecture, allows you to think about the concepts, tells me if you are understanding the material
– It has been proven to work: students get a better understanding of physics
More on clickers
Pre/post FMCE (Sp04)
0
10
20
30
40
50
60
0 12 24 36 48 61 73 85 97
Score (%)
# o
f stu
den
ts
Pre
PostMean our class
Force-Motion Concept Evaluation
Learning Gains
R. Hake, ”…A six-thousand-student survey…” AJP 66, 64-74 (‘98).
<g> = post-pre 100-pre
red = trad, blue = interactive engagement
FCI
at CU
Phys 1110 normalized learning gains (on nationally validated exam “FMCE”)
3 CU classes: all w. clickers in lecture, but different recitation styles: gain(1)= .66 +/-.02 g(2)= .585 +/-.02 g(3)= .45 +/-.02 Course (1) with Tutorials has highest gains. Course (2) is 8 points (several sigma’s) worse Course (3) (trad recit.) => significantly lower gains. (but still, double nat’l standards!)
distribution of g: compared
0
5
10
15
20
25
30
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
normalized gain
% o
f stu
dents
SP04
FA04
SP05
UW Tutorials
Trad rec.
Small groups
16
Getting assistance • The instructors, TA’s, & LA’s are here to help you
– but you need to ask • Physics help room in G2B90 contains instructors,
TA’s, & LA’s who can help with physics problems and computers for entering CAPA answers
• Instructors have office hours for physics or other questions – can also schedule appointment
17
Clicker question 1 Q. Do you have a working clicker?
A. Yes B. No C. Don’t know
Set frequency to BA
To set frequency, hold down on/off button until power light starts flashing. Then enter BA and vote light should flash green and power light should be solid blue. Can only set frequency after the first question of the class has started.
Can vote as often as you like during the allowed time; only the last vote counts
18
Physics is an Experimental Science
• Observations or experiments produce data – and data needs to be confirmed. Exciting
possibility now is superluminal neutrinos. • Physicists construct theories to explain the data
and predict the results of future experiments • As more data are obtained, theories will be
discarded, verified, or modified • Theories must be falsifiable – this is why an
appeal to the supernatural is not science
19
Goals for this course • Learn to think like a scientist, be curious about
your surroundings. • Develop good problem solving skills. • Gain an understanding of “mechanics” including:
– Linear and rotational motion, momentum, acceleration, and forces.
– Energy concepts including work, kinetic energy, potential energy, and heat.
20
Things you will learn: • How a rocket works • Why you get thrown off
a fast merry-go-round • Why a spinning top
doesn’t fall down • Why cars have crumple
zones • Why the boiling point of
water is lower at high altitude
21
First, some basics: units • Measurements of anything must have units to be
meaningful • A speed of 5 means nothing while speeds of 5 mph, 5
km/h, or 5 furlongs/fortnight have meaning • We will use SI (International System of Units) units
such as: – mass in kilograms (kg) – length in meters (m) – time in seconds (s)
The Babylonians and Sumerians had a system in which there were 60 shekels in a mina and 60 minas in a talent (in Ancient Greece one talent was 26 kg of silver). The Roman talent consisted of 100 libra (pounds) which were smaller in magnitude than the mina.
22
SI units and prefixes • Prefixes change base unit by some power of 10
and power is divisible by 3 (except cm = 10-2 m) – 1 km = 1000 m = 103 m – 1 µg = 0.000001 g = 10-6 g – 1.21 gigawatts = 1.21 GW = 1.21×109 watts
• Appendices in text have units and prefixes
23
More on units • Units must be the same on either side of =
d = v is distance = velocity and has units m = m/s
d = vt is distance = velocity times time and has units m = m/s·s
• Use this fact to make sure that an equation makes sense
24
Unit conversions • A horse is galloping at 10 m/s. How far does it
travel in 1 hour? • d = vt so d = 10 m/s · 1 hour = 10 m/s · hr.
Correct but not that useful. • Note that and can multiply by 1
• d = vt so
• This is the easiest way to think of unit conversions
25
Uncertainties • Like units, measurements have no meaning
without uncertainties • Suppose I weigh myself at 80.5 kg and I know
the scale is accurate to 0.1 kg – Can write – Writing 80.5 implies the same thing (that the
uncertainty is on the farthest right digit) – Writing 80.500 would be incorrect because it
implies an accuracy of 0.001 kg – CAPA needs 1% accuracy €
80.5 ± 0.1 kg
26
Significant figures • Rules for counting sig figs (by example):
– 1 sig fig: 0.3 m, 0.0003 km, 300 mm, 3 dm – 2 sig figs: 0.31 kg, 0.00042 s, 510 g, 1.0 µs, 3.0×10-5 m – 3 sig figs: 333 m/s, 0.0813 m/s2, 189 ng, 2.15×104 m
• Rule for addition/subtraction: Answer has the same number of digits to the right of the decimal point as the least well measured value so 57.3 g + 21 g = 78 g.
• Rule for multiplication/division: Answer has the same number of significant figures as the value with the fewest significant figures so 0.3 cm · 0.75 cm = 0.2 cm2.
27
Clicker question 2 Q. What is 2 m × (3.5 m + 5.5 m)?
A. 18 m B. 11 m C. 20 m2
Set frequency to BA
D. 2 × 10 m3 E. 1.8 × 10 m2
3.5 m + 5.5 m = 9.0 m
2 m × 9.0 m = 20 m2 or 2×101 because 18 m2 would have two significant figures but 2 m only has one.
Recitation Tomorrow • Read the syllabus before tomorrow. • Get your CAPA assignment • Obtain and register your clicker. • Attend your Recitation – get points for
participation.
28
