00 introduction
my expectations
your expectations
grading
on-line quizzes
what I expect from you: active learning
before class
read chapter before we begin
warm-up quiz (on-line) on reading*
during class
think/pair/share quizzes*
be prepared with question
20 Momentum and Impulse
Conservation laws common: e.g. mass:
pour 100 g of vinegar into 100 g of oil.
what's the mass of the vinaigrette?
Many other physical quantities often conserved
momentum
angular momentum
energy
charge
momentum
p
v
m
vector: direc
14 projectile motion
no horizontal acceleration: constant horizontal velocity
demo: knock 2 balls off a table (different v)
m
g
a
=
=
g
=
m
m
acceleration is vertically downwards
F net
listen for the impacts. does one hit first?
follow ups:
workbook probl
11 Mass and weight
mass:
a
F i=m
i
weight: force of gravity
w=m
g
same mass m in both formulas
direction: downwards
coincidence? General Relativity?
apparent weight: normal force of scale on feet
try bouncing on a scale!
Inclined plane
#1
#2
#3
#1: (A)
10 Applying Newton's Laws
The basic equations are
Newton's 1st law
0
F = F i =
net
i
or Newton's 2nd law
F = F i = m
a
net
i
Equation hunting won't solve these problems
Needed: Problem solving strategy
apply the same pattern
vary the approach to match th
st
nd
09 Newton's 1 and 2 laws
Issues:
Is a force needed to produce uniform motion?
What happens to motion if a constant force is applied?
Demonstration
nd
Newton's 2 law
F
net
1
a
= Fi
=
m
mi
observations from experiment:
more mass lesser acceleration
mo
05 problem solving: constant a
model: particle model
visualize: shift between these as needed
motion diagram
pictorial representation: label
v fs = v is a s t
solve
1
2
s f = si v is t a s t
2
assess
2
2
v fs = v is 2 a s s
units? sensible? believable?
04 position, velocity and acceleration
if v is constant
s=v s t
displacement
change in position
area under v(t)
workbook:
2.2b page 2-3
displacement when v isn't constant
tf
s f = si v s t dt
ti
integral = area
under curve
between curve and
axis
integrat
01 Motion
diagrams
use movie to study
motion
fixed time between
frames
don't pan the camera!
usually 1/30th of a sec
strobe pictures are
faster
faster objects
have greater position
change between frames
Which car is going faster, A or B? Assume there are
27 Conservation of Energy
K f U f E th = K i U i W ext
scenarios:
what's the system?
(A) + (B) - (C) 0
push a block across a
table at constant speed
DK=?
DU=?
a block slides to a halt
Wdiss = ?
pick up a block, and
place it on a ledge
Wext = ?
toss a bloc