General Physics 1
A yo-yo on a horizontal surface,
iniCally at rest
Pull gently on the string as shown: which way
will the yo-yo move?
1) Roll to the right
T
2) Roll to the le<
3) Remain in place
N W FS

General Physics 1
Forces cause linear accelera2on;
torques cause angular accelera2on
Newtons 2nd Law for linear mo2on applies even
in the presence of torques
MaCM = Fext, net
In addi2on, Newtons 2nd Law for

Solution to Problem Gymnast
1)Since whole system is in balance, we can write the equilibrium equation for torques of
forces:
X
Mi = 0
i
where Mi - torque of each force.To nd the force the left support exerts on the beam, we
need to write the above equatio

General Physics 171.101
Midterm Exam 2
March 15, 2012
Answer all three questions. VERY IMPORTANT: YOU MUST SHOW AND EXPLAIN ALL
YOUR WORKING TO GET FULL CREDIT. Partial credit will given for partially-correct
a

Week V Homework Solutions
March 12, 2013
Graders: Atakhodjaev, Sung, Setlow
Solution to Problem Block On Incline
5.1.1) The work done by tension on horizontal oor is
WT = T d cos
5.1.2) According to Work-Energy theorem WT = KE, where KE- kinetic energy o

Announcements
1) For Friday: Prelecture 24
2) Homework 12 due April 30th at 10 pm
3) Midterm exam will be handed back in secBon
tomorrow
A tsunami is a fast moving ocean wave train that is p

General Physics 1
Air ow
P
Q
R
How do the air veloci9es at P, Q , and R compare?
1) All the same
2) VP = VR > VQ
3) VQ > VP = VR
4) VP > VQ > VR
Air ow
P
Q
R
How do the air veloci9es at P,

General Physics 1
Condi2ons for sta2c equilibrium
1) Net force = 0
2) Net torque = 0 (around any axis)
Consider the three situa2ons shown in the gure. Three forces act on the triangular
object in dierent way

Week XIII Homework Solutions
May 5, 2013
Graders: Atakhodjaev, Setlow
Solution to Problem 13.1 YouTube
13.1.1) The absolute pressure at the bottom of the tube is P = PA + w gh1 .
13.1.2) The absolute pressure in the water at the water-oil interface is P =

General Physics 171.101
Final Exam
May 16, 2012
Answer all five questions. VERY IMPORTANT: YOU MUST SHOW AND EXPLAIN ALL
YOUR WORKING TO GET FULL CREDIT. Partial credit will given for partially-correct
answers.

Announcements
1)
2)
3)
Next Monday: Prelecture 22
Homework 11 posted today and due next Tuesday
Midterm exam on Friday: will 11:05 11:55 work?
A mass on a spring
A dierenFal equaFon
d2x
a = 2 = F /m = kx /m = 2 x
dt
wh

General Physics 1
Final exam
1)
2)
3)
4)
The nal exam is 2 5 pm, Tues May 14th in this room
The style will be similar to the midterm exams
Open book, open notes, calculator allowed, laptop
not allowed
Will

General Physics 171.101
Midterm Exam 1
February 23, 2012
Answer all three questions. VERY IMPORTANT: YOU MUST SHOW AND EXPLAIN
ALL YOUR WORKING TO GET FULL CREDIT. Partial credit will given for partially-
correct

General Physics 1
Announcements
1) Prelecture / checkpoint 19 for Wednesday
2) Midterm 3, covering prelectures 14 20, will be
given IN CLASS on Friday April 19 at 11 am
(Open book, open notes, as before)
3)

General Physics 1
Where we are
Work done by non-conserva7ve forces
Zero if perpendicular to the displacement
Non-zero otherwise
Nega7ve for a fric7onal force
Macroscopic Work done by Friction
f
f
Heat is just the kine

General Physics 1
If the total force
is zero, the CM
wont accelerate
Center of mass equa;on
for a closed system
MaCM = Fnet, ext
M = total mass (constant in a closed system)
Fnet, ext = sum of all extern

General Physics 1
Selec0ons from the discussion forum
This was by far the most dicult pre-lecture and ideally, I
would like to review a bit of everything in class. I would like
for us to more clearly dene work -

Announcements
PLEASE TAKE A MID-SEMESTER QUESTIONNAIRE
AND FILL IT OUT ANONYMOUSLY NOW
1) Prelecture/checkpoint 15 by Wed March 27th
2) Homework 7 due March 26th at 10 pm
3) Midterm Exam 2 will be graded by

General Physics 1
Announcements
Last years Midterm Exam 2 now posted on
Blackboard
Review session tomorrow 5 7 pm in
Bloomberg 272 (this auditorium)
Prelecture/checkpoint 14 for Friday (aLer the
exam)
A moving

General Physics 1
Announcements
1) Please view Prelecture 13 by next Monday
2) Homework 6 due March 12
3) Midterm Exam 2 is Thursday March 14 at 8 am
Prelectures/Units 7 13
Open book / open notes, exa

General Physics 1
Rolling mo3on
Can be viewed as a combina3on of transla3on
of the CM and rota3on about the CM
What was the direc3on of the fric3on force
by the ramp on the hoop rolling down?
A. Up the ramp

Announcements
1) Thanks for your though5ul responses to the
ques9onnaire
2) Midterm exams returned today; example
solu9ons and scores are on Blackboard
3) Oce hours: today and Wednesday 1 - 2:45 pm
or by appointment

General Physics 1
Announcements
Midterm Exam 2 will take place tomorrow at 8am
for all sec>ons in this auditorium
Open book/open notes (bring whatever you want to
bring including homework problems)
Strictly no ele

General Physics 1
Free-body diagram shows forces ac8ng
on a single object (no third law pairs)
N
T
f
W = mg
ma = N + f + T + W (vector sum)
Types of forces
Weight, W = mg (downwards)
Tension, T

Announcements
1) Midterm exams graded: example solu7ons
posted
2) Overall grade column added to blackboard
is based on performance to date
(about 25% of the way through the semester)
3) No7fy me via email of

General Physics 1
Dynamics: Newtons Laws
5.3.1. A pipe is bent into the shape shown and oriented so that it is si?ng horizontally on a
table top. You are looking at the pipe from above. The interior of the pip

Welcome to General Physics
Please sit in front seven rows of the middle sec6on
of sea6ng. Move in to the center, to make room for
others. (If you need to exit during the lecture, dont
worry . people will let

General Physics 1
Feedback, please
Hows the pace of the course?
A. Way too slow
B. A liAle too slow
C. Its about what it should be
D. A liAle too fast
E. Way too fast
Am I speaking loudly and clearly enough?