Clifton Bluhm
“
Inertia
in
define
MOMENTUM
Define
IMPULSE
determine which quantities affect
momentum
.
determine which quantities affect
impulse
.
quantify
momentum
with an equation.
quantify
impulse
with an equation.
I can . . .
differentiate elastic from inelastic collisions
using concepts of
Which vehicle has more
momentum
?
Momentum
is a Function of
MASS
www.toyota.com
Which car has more
momentum
?
Momentum
≡
UNITS
Momentum
=
kg
·
m/s
Momentum
=
kg
·
m
s
Mass
? ? ?
·
Velocity
“
Inertia
in
http://www.waynet.org/waynet/spotlight/2001/images/08/smileytruck-closeup640.jpg
Zero Velocity
Implies
Zero
Momentum
http://brd3.chosun.com/bemil/files/BEMIL025/upload/A%20Tomahawk
Tomahawk Cruise Missile
Mass = 1000 kg
Velocity = 100 m/s
Semi Truck
Mass = 5000 kg
Velocity = 20 m/s
Momentum = 100,000 kg·m/s
Momentum = 100,000 kg·m/s
http://www.rit.edu/~andpph/photofile-c/bullet-rifle-22-1a.jpg http://wilsonscc.com/Giant%20Turtle%20copy.jpg
300 m/s
.01 kg
.03 m/s
100 kg
.22 Caliber Bullet
Giant Turtle
3 kg·m/s
.22 Caliber Bullet
Giant Turtle
http://www.rit.edu/~andpph/photofile-c/bullet-rifle-22-1a.jpg
1,000 kg
(
30 m/s
)
1,000 kg
(
50 m/s
)
30,000 kg·m/s
50,000 kg·m/s
Momentum
Before
Momentum
After
Change in
Momentum
(Δp)
Change in
Momentum
= m·ΔV
=
1000 kg
(
20 m/s
)
=
20,000 kg·m/s
a
=
m
f
a
=
ΔV
t
f
m
ΔV
t
=
m
·
ΔV
=
f
·
t
Δ
Momentum
=
f
·
t
Impulse
=
f
·
t
Newton’s 2
nd
Law
Definition of Acceleration
Impulse
≡ Δ
Momentum
An
Impulse
of
250 N·s
CAUSES a
change in
Momentum
of
250 kg·m/s
Push with
100 N
for
1 s
.
Push with
50 N
for
2 s
.
Push with
25 N
for
4 s
.
Push with
10 N
for
10 s
.
Push with
5 N
for
20 s
.
List
5
ways to apply
Time (seconds)
F
o
rc
e
(N
ew
to
n
s)
Time (seconds)
F
o
rc
e
(N
ew
to
n
s)
Impulse = Force ·Time
Impulse = ½ Maximum Force ·Time
= Average Force ·Time
Time (seconds)
F
o
rc
e
(N
ew
to
n
s)
Time (seconds)
F
o
rc
e
(N
ew
to
n
s)
40 N
30 N
20 N
10 N
-10 N
-20 N
1 s
2 s
3 s
4 s
5 s
6 s
Impulse = 80 N·s
If the object had a
change in velocity of 30 m/s
,
what was the object’s
mass
?
Δp
= m ·
Δv
60 kg·m/s
= m ·
30 m/s
m = 2 kg
Force
Sensor
Which object would have a larger change in
momentum if the man pushed for 3.0 s?
A) Car
Which object would have a larger change in
momentum at the finish line?
A) Car
Who had the larger
IMPULSE
?
Momentum
=
mass
·
velocity
=
70 kg
·
30 m/s
=
2100 kg·m/s
Who had the larger
Force
of impact?
Who had the larger
TIME
of impact?
Momentum =
ZERO
Impulse
=
f
·
t
Impulse
= ∆
Momentum
Momentum =
ZERO
Momentum
=
mass
·
velocity
=
70 kg
·
30 m/s
Impulse
=
f
·
t
http://www.netcar.co.il/img2/milon/25A%20front%20air%20bag.jpg
You stop in
0.5 seconds
with an airbag,
and you stop in
0.05 seconds
without
.
If without an airbag there is
2000 N
of
force on you, how much force will there
be
with an airbag
?
200 N
Impulse
=
f
·
t
=
f
·
t
http://www.rescate.com/rappel.jpg
http://www.rock-climbing-courses.co.uk/images/galler4.jpg
Who had the larger
IMPULSE
?
Who had the larger
IMPULSE
?
Who received a larger
FORCE
?
Who had a larger
IMPULSE
?
+
-+
-+
30,000 kg·m/s
-
30,000 kg·m/s
+
30,000 kg·m/s
-
30,000 kg·m/s
Positive and Negative
Momenta
What was the
IMPULSE
on the car.
-50
,00
0
-40
,00
0
-30
,00
0
-20
,00
0
0
+1
0,0
Which ball had a larger
IMPULSE
?
+
10 kg·m/s
-
10 kg·m/s
0 kg·m/s
+
10 kg·m/s
0
kg·m/s
∆
Momentum
=
20 kg·m/s
∆
Momentum
=
10 kg·m/s
Impulse = 20 N·s
Impulse
=
f
·
t
2·
Impulse
=
2
(
f
·
t
)
http://www.theamericangym.com/BYtramps.htm
CONSERVATION:
Preservation from loss
CONSERVATION:
Preservation from loss
Conservation of
Momentum
Total
Momentum
Before
= Total
Momentum
After
p
A
Before
+ p
B
Before
= p
A
After
+ p
B
After
m
A
·
v
A
+
m
B
·
v
B
=
m
A
·
v
A
+
m
B
·
v
B
A
B
Total
Momentum
Before
= Total
Momentum
After
2 kg
(
0
m/s
)
+
.01 kg
(
0
m/s
) =
2 kg
(
-1 m/s
)
+ (
.01 kg
·
200 m/s
)
p
gun
+
p
Bullet
=
p
gun
+
p
Bullet
Zero BEFORE = Zero AFTER
Total
Momentum
Before = Total
Momentum
After
Zero BEFORE = Zero AFTER
Total
Momentum
Before = Total
Momentum
After
Zero BEFORE = Zero AFTER
Total
Momentum Before
= Total
Momentum After
m
1
·
v
1
+
m
2
·
v
2
= (
m
1
+
m
2
)·
v
Inelastic Collisions
(Sticking)
stick
Total
Momentum
Before
= Total
Momentum
After
m
1
·
v
1
+
m
2
·
v
2
= (
m
1
+
m
2
)·
v
Total
Momentum Before
= Total
Momentum After
1 ·
1
+
1
·
0
= (
1
+
1
) ·
v
v = ½
m
1
·
v
1
+
m
2
·
v
2
= (
m
1
+
m
2
)·
v
Total
Momentum
Before = Total
Momentum
After
1 ·
1
+
2
·
0
= (
1
+
2
) ·
v
v = ⅓
m
1
·
v
1
+
m
2
·
v
2
= (
m
1
+
m
2
)·
v
Total
Momentum
Before = Total
Momentum
After
2 ·
1
+
1
·
-1
= (
2
+
1
) ·
v
v = ⅓
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