phy 113 a general physics i 9-9:50 am mwf olin 101 plan for lecture 2: some announcements
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PHY 113 A General Physics I 9-9:50 AM MWF Olin 101 Plan for Lecture 2: Some announcements Chapter 2 – Motion in one dimension Position, time, velocity General examples Constant velocity. Some updates/announcements According to the class vote -- changes to exam schedule:. - PowerPoint PPT PresentationTRANSCRIPT
PHY 113 A Fall 2012 -- Lecture 2 18/31/2012
PHY 113 A General Physics I9-9:50 AM MWF Olin 101
Plan for Lecture 2:
Some announcements
Chapter 2 – Motion in one dimension
1. Position, time, velocity
2. General examples
3. Constant velocity
PHY 113 A Fall 2012 -- Lecture 2 28/31/2012
Some updates/announcements
According to the class vote -- changes to exam schedule:
PHY 113 A Fall 2012 -- Lecture 2 38/31/2012
Some updates/announcements
According to class vote – changes to exam schedule:
PHY 113 A Fall 2012 -- Lecture 2 48/31/2012
Tentative list of exam dates:
1. Wednesday, September 19, 20122. Monday, October 8, 20123. Friday, November 2, 20124. Wednesday, November 28, 2012
PHY 113 A Fall 2012 -- Lecture 2 58/31/2012
iclicker exercises:Webassign Experiences so far
A. Have not tried itB. Cannot loginC. Can loginD. Have logged in and have completed one or more
example problems.
Textbook Experiences
E. Have no textbook (yet)F. Have complete physical textbookG. Have electronic version of textbookH. Have Volume I physical textbookI. Textbook is on order
PHY 113 A Fall 2012 -- Lecture 2 68/31/2012
Starting September 3, 2012
Schedule for Physics 113 Tutorials5-7 PM in Olin 101
Sunday Monday Tuesday Wednesday Thursday Friday
Loah Stevens Jiajie Xiao Jiajie Xiao Stephen Baker Stephen Baker Loah Stevens
PHY 113 Labs start September 3, 2012(Please see Eric Chapman in Olin 110
[email protected] for all of your laboratory concerns)
First Webassign sets “due” on Friday, Sept. 7th
PHY 113 A Fall 2012 -- Lecture 2 78/31/2012
Motion in one-dimension
t(s) x(m)
A 0 30
B 10 52
C 20 38
D 30 0
E 40 -37
F 50 -53
PHY 113 A Fall 2012 -- Lecture 2 88/31/2012
Graphical representation of position (displacement) x(t)
t (s)
PHY 113 A Fall 2012 -- Lecture 2 98/31/2012
Comment: Your text mentions the notion of a “scalar quantity” in contrast to a “vector quantity” which will be introduced in Chapter 3. In most contexts, a scalar quantity – like one-dimensional distance or displacement can be positive or negative.
Another comment: Your text describes the time rate of change of displacement as “velocity” which, in one-dimension is a signed scalar quantity. In general “speed” is the magnitude of velocity – a positive scalar quantity.
PHY 113 A Fall 2012 -- Lecture 2 108/31/2012
Graphical representation of position (displacement): x(t) time rate of change of displacement = velocity: v(t)
t (s)
dt
dx
t
txttxtv
Δt
)()()(
:velocity
lim0
4 20
4040
2040
)20()40()(
m/s-s
mm--ss
xxtv
PHY 113 A Fall 2012 -- Lecture 2 118/31/2012
Instantaneous velocity
t (s)
vA
vB
vC
vE
vF
vD
PHY 113 A Fall 2012 -- Lecture 2 128/31/2012
Demonstration of tangent line limit
dt
dx
t
txttxtv
Δt
)()()(
: velocityousInstantane
lim0
PHY 113 A Fall 2012 -- Lecture 2 138/31/2012
Average velocity versus instantaneous velocity
dt
dx
t
txttxtv
Δt
)()()(
: velocityousInstantane
lim0
AB
AB
AB
t
tB
A
tt
txtx
tt
dttv
v
B
A
)()(
)(
: velocityAverage
PHY 113 A Fall 2012 -- Lecture 2 148/31/2012
Average velocity
AB
ABB
A tt
txtxv
)()(
:stated previous The iclicker exercise:
This results is:
A. ExactB. Approximate
PHY 113 A Fall 2012 -- Lecture 2 158/31/2012
Webassign Example
PHY 113 A Fall 2012 -- Lecture 2 168/31/2012
Instantaneous velocity using calculus
2765)(
:Suppose42 ttttx
38146)( ttdt
dxtv
PHY 113 A Fall 2012 -- Lecture 2 178/31/2012
Anti-derivative relationship
:m/s 3.0 and 0 suppose -- Example
)( :Then
:Suppose
motionelocity Constant v
00
00
0
vx
tvxtx
vdt
dx
t
x