We
We have
have the
the first
first exam
exam next
next Friday.
Friday. II will
will post
post two
two practice
practice exams
exams
w/answers
w/answers on
on Cobra
Cobra later
later today.
today. II will
will also
also distribute
distribute a
a hardcopy

In Lecture 5 we looked at the constantpressure and constant-volume processes.
Today we get into the constant-temperature
and adiabatic processes.
With the Q and W information from each of
these four, we can quantify the efficiency
of many physical engines

Physics 142 Exam One
Name _
Consider all data and constants given to be exact numbers.
Show work to receive credit for your answers.
Work answers to 3 significant figures. Remember units.
TK = TC + 273o
PV=nRT
Q=mcT
Q
kA(TH-TC)
Q
=
t
L
cice = 0.53
Q
t
cal

Physics 2101
Section 3
May 7th: Chap. 20
Announcements:
Final Exam: May 11th
(Tuesday), 7:30 AM at HoweHoweRussell 130
Make up Final: May 15th
(Saturday) 7:30 AM at Nicholson
119
Chapter 20
20Irreversible processes
Final Exam for those who need
extende

Today we look at a couple of examples that should
help you see how Gauss works for spherical and cylindrical
geometry. Well hold off on the planar case until
Lecture 16, so we have the chance today to settle some
issues.
There are many nuances to this Gau

In the homework, youve been
using Coulombs Law to find the
net force on charges.
The 2D vector addition thing is
usually rusty at this point in
142, so the HW theme this
week is to brush up on x and y
components.
In doing #11, you notice that
there were 3

F =
k Q1 Q2
2
r
^
r
we have been working with Coulombs Law
this k constant is 9x109
F =
Q1 Q2
40
2
r
^
r
But you will also see it represented like this,
using a different constant.
k =
0 =
1
40
1
4k
= 9x10
9
= 8.85x10
-12
Ive spared you the units here th

An electron with a speed of 5x106 m/s is launched as
shown into a region with an upward electric field
of 500 N/C. Find yf.
I know many of you got the answer here.
But I wanted to show some details.
yf
40o
20 cm
Everywhere the electron goes, it
finds the

Exam 2 is next Friday. It will cover Ch 21,22, and 23.
So we have a fair amount of time to digest all of
the Gauss Law stuff.
This Lecture 17 has two objectives. One is to go through
the planar non-conducting example posed in Lecture 16.
The other is to g

In the HW for today, you found the
electric field due to the presence of a set
of source charges.
Today we look at the electric field due to
the presence of a continuous line of charge.
This can be done using the Ch 22 stuff that
you have been doing, or i

Lecture 13 closed with a challenging problem.
Non-conducting cylinder with a charge density.
If you were able to get it, youre off to a great
start in your understanding of Gauss Law.
The next few slides should help with your conceptual
understanding of c

A suggestion for todays Lecture 16 is to view it
in Normal mode in PowerPoint instead of in SlideShow.
Certain features show up jumbled in SlideShow and in the
printed version, but things look fine in Normal mode.
We have a flat sheet of non-conducting
ma

In Lecture 11
you did this example
where you found
the electric field
at a point,
with Q = +5x10-6 C.
+Q
+Q
A
-Q
+Q
80 cm
Each charge
contributed a vector
field to the point
and we added the
fields as vectors
to find the
resultant.
+Q
+Q
-Q
+Q
80 cm
+Q
+Q

We have the first exam next Friday. Two practice exams w/answers are
posted on Cobra. I will also distribute a hardcopy of one of the practice exams
at the lab sessions Tuesday and Thursday. There will also be two lab
assessments at the beginning of the l

A heat engine is a system that
operates in a repeatable cycle
of thermodynamic processes.
The second law of
thermodynamics states that this
series of processes cannot
convert fuel into work with
100% efficiency.
These next three sessions are devoted to
un

The class average for Exam 1 was 76.8%.
You are eligible to drop your lowest exam of the
semester, provided you have no more than 5
lecture absences during the term.
Also, if you arrive more than 10 minutes late for a
lecture, you will be counted as being

Three practice exams are available on Cobra.
Hardcopy of one will be available at lab this week.
Lab assessment this week on single-variable
statistics.
Exam Friday (here in M124).
You can start the exam 3 minutes before the hour
and we will finish 53 min

A heat engine is a system
that operates in a
repeatable cycle of
thermodynamic processes.
The second law of
thermodynamics states that
this series of processes
cannot convert fuel into
work with 100% efficiency.
These next three sessions are devoted
to un

Your quiz points accumulate each day.
The first correct quiz submitted by a group earns 3 points, the second earns a
2, and every other correct submission scores a 1. To make it interesting, you
can wager any or all of the points that you have previously

Newtons Law of
Gravitation
F
=
G m1
m
r22
-11
G = 6.67x10-11
(m33)/kg/s22
force
force of
of attraction
attraction
between
between masses
masses
F
=
m
1
G m1
m
r22
r
distance
distance
of
of separation
separation
force
force is
is
inverse-square
inverse-sq

This week starts the schedule
of lab experiments.
There is no lab manual or notebook
to purchase each week
a packet will be distributed.
You do need to bring a calculator
(preferably a TI) that can do
statistical operations.
Your quiz points accumulate ea

Welcome
to Physics 142
Spring 2015
Lets start with something that
may be familiar.
PV = nRT
Otherwise known as
the Ideal Gas Law.
Pressure
PV = nRT
Pressure can be expressed in a variety of
ways, one being lbs per square inch.
Can you express pressure in

Homework assignments are due at
each lecture session.
HW is not handed in for a grade, but
the quizzes will be related to HW
problems. Its a good idea to keep a
notebook of completed HW problems.
Next week starts the schedule
of lab experiments. I would a

In Lecture 5 we looked at the
constant-pressure and constantvolume processes.
Today we get into the constanttemperature and adiabatic processes.
With the Q and W information from
each of these four, we can quantify
the efficiency
of many physical engines.

Physics 142 Exam One
Name _
Consider all data and constants given to be exact numbers.
Show work to receive credit for your answers.
Work answers to 3 significant figures. Remember units.
TK = TC + 273o
PV=nRT
Q=mcT
Q
kA(TH-TC)
Q
=
t
L
cice = 0.53
Q
t
cal

Newtons Law of Gravitation
F =
G m1 m2
2
r
G = 6.67x10-11 (m3)/kg/s2
force of attraction
between masses
F =
m1
G m1 m2
2
r
r
distance
of separation
force is
inverse-square
m2
F =
m1
G m1 m2
2
r
^
r
forces equal and opposite
Newtons Third
use radial unit

Two practice exams are available on Cobra.
Hardcopy of one will be available at lab this week.
Two lab assessments in lab this week.
Exam Friday (here in M124).
You can start the exam 3 minutes before the hour and we
will finish 53 minutes after the hour.

Exam 2 this Friday.
It will cover Chapters 21, 22 and 23.
Relevant material can be found in Lectures 9 through 17,
as well as the homework problem found at the end
of Lecture 18.
Two practice exams have been posted on Cobra.
I will have copies of one of t