Transcript momentum - Cloudfront.net

MOMENTUM
Action and Reaction Forces
Newton’s Third Law
Newton's Third
Law of Motion
(Law of Action &
Reaction)
[Law of Forces
acting in Pairs]
Newton's
rd
3
Law of Motion says:
for every action, there is
an equal and opposite
reaction.
Forces act in pairs. One force is
called the action force and the
other is called the reaction force.
MOMENTUM
Momentum is a property a
moving object has because
of its mass and velocity.
MOMENTUM
Which would hurt more??
MOMENTUM
Momentum is a property a moving object
has because of its mass and velocity.
Momentum can be calculated by :
P = momentum (kgm/s)
m = mass (kg)
v = velocity (m/s)
MOMENTUM
What is the momentum of a 5 kg ball that
has a velocity of 15m/s?
G
U
E
S
S
Momentum practice problems
What is the momentum of a 5 kg ball that has a
velocity of 15m/s?
G
U
P= ?
M= 5kg
V= 15m/s
E
P=MV
S
S
Momentum practice problems
What is the momentum of a 5 kg ball that has a
velocity of 15m/s?
G
U
P= P
M= 5kg
V= 15m/s
E
P=MV
S
P = 5 x 15
S
Momentum practice problems
What is the momentum of a 5 kg ball that has a
velocity of 15m/s?
G
U
P= P
M= 5kg
V= 15m/s
E
P=MV
S
P = 5 x 15
S
75 kg • m/s
MOMENTUM
What is the mass of a box that has a
momentum of 10 kg • m/s and a
velocity of 5m/s?
G U
E
S
S
MOMENTUM
What is the mass of a box that has a
momentum of 10 kg • m/s and a
velocity of 5m/s?
G U
P= 10 kg •m/s
M= M
V= 5m/s
E
P=MV
S
S
MOMENTUM
What is the mass of a box that has a
momentum of 10 kg • m/s and a
velocity of 5m/s?
G U
P= 10 kg •m/s
M= M
V= 5m/s
E
P=MV
S
10 = M x 5
S
MOMENTUM
What is the mass of a box that has a
momentum of 10 kg • m/s and a
velocity of 5m/s?
G U
P= 10 kg •m/s
M= M
V= 5m/s
E
P=MV
S
10 = M x 5
10 = M x 5
5
5
S
MOMENTUM
What is the mass of a box that has a
momentum of 10 kg • m/s and a
velocity of 5m/s?
G U
P= 10 kg •m/s
M= M
V= 5m/s
E
P=MV
S
10 = M x 5
10 = M x 5
5
5
S
2 kg
MOMENTUM
What is the velocity of a child that has a mass of
20kg and a momentum of 50 kg •m/s ?
G U
E
S
S
MOMENTUM
What is the velocity of a child that has a mass of
20kg and a momentum of 50 kg •m/s ?
G U
P= 50 kg •m/s
M= 20kg
V= V
E
P=MV
S
S
MOMENTUM
What is the velocity of a child that has a mass of
20kg and a momentum of 50 kg •m/s ?
G U
P= 50 kg •m/s
M= 20kg
V= V
E
P=MV
S
50 = 20 x V
S
MOMENTUM
What is the velocity of a child that has a mass of
20kg and a momentum of 50 kg •m/s ?
G U
P= 50 kg •m/s
M= 20kg
V= V
E
P=MV
S
50 = 20 x V
20 20
S
MOMENTUM
What is the velocity of a child that has a mass of
20kg and a momentum of 50 kg •m/s ?
G U
P= 50 kg •m/s
M= 20kg
V= V
E
P=MV
S
50 = 20 x V
20 20
S
5/2 or 2.5 m/s
Copy this question and the steps to
solve! This question is on the
assignment, quiz, review and test!
If a Miata (900kg) at 30 m/s runs headon into a Civic (1200kg) and neither car
moves after the collision, what is the
velocity of the Civic ?
Given/ Miata:
Miata
M Vthe momentum of the
Our first job isPto= find
Miata…………
If a Miata (900kg) at 30 m/s runs headon into a Civic (1200kg) and neither car
moves after the collision, what is the
velocity of the Civic ?
Given/ Miata:
P= ?
M=900 kg
V= 30 m/s
Miata: formula
P=MV
Our first job is to find the momentum of the
Miata…………
If a Miata (900kg) at 30 m/s runs head-on
into a Civic (1200kg) and neither car
moves after the collision, what is the
velocity of the Civic ?
Given/ Miata:
P= ?
M=900 kg
V= 30 m/s
Miata: formula
P=MV
SUB
P = 900 x 30
Our first job is to find the momentum of the
Miata…………
If a Miata (900kg) at 30 m/s runs head-on
into a Civic (1200kg) and neither car
moves after the collision, what is the
velocity of the Civic ?
Given/ Miata:
P= ?
M=900 kg
Miata: formula
P=MV
SUB
P = 900 x 30
ANS/UNITS
P=27000 Kg * m/s
V= 30 m/s
Since they did NOT move after the
collision, their “momentums” must
have been EQUAL!
If a Miata (900kg) at 30 m/s runs head-on into a
Civic (1200kg) and neither car moves after the
collision, what is the velocity of the Civic ?
Given/ Miata:
P= P
M=900 kg
Miata: formula
P=MV
SUB
P = 900 x 30
ANS/UNITS
P=27000 Kg * m/s
V= 30 m/s
Since they did NOT move after the
collision, their “momentums” must have
been EQUAL!
Given/Civic: P = 27,000 kg •m/s
If a Miata (900kg) at 30 m/s runs head-on into a
Civic (1200kg) and neither car moves after the
collision, what is the velocity of the Civic ?
Since they did NOT move after the
collision, their “momentums” must have
been EQUAL!
Given/Civic: P = 27,000 kg •m/s
Given/Civic:
P = 27,000 kg • m/s
M = 1200kg
V=?
If a Miata (900kg) at 30 m/s runs head-on into a
Civic (1200kg) and neither car moves after the
collision, what is the velocity of the Civic ?
Since they did NOT move after the
collision, their “momentums” must have
been EQUAL!
Given/Civic: P = 27,000 kg •m/s
Given/Civic:
P = 27,000 kg • m/s
M = 1200kg
V=?
P=mv
27,000 = 1200 x V
If a Miata (900kg) at 30 m/s runs head-on into a
Civic (1200kg) and neither car moves after the
collision, what is the velocity of the Civic ?
Since they did NOT move after the
collision, their “momentums” must have
been EQUAL!
Given/Civic: P = 27,000 kg •m/s
Given/Civic:
P = 27,000 kg • m/s
M = 1200kg
V=V
P=mv
27,000 = 1200 x V
1200
1200
V = 22.5 m/s
That was the
Velocity of the
Civic!
The Law of Conservation of Momentum
- the total amount of momentum of a
group of objects does not change unless
outside forces act on the objects.
(Ex – momentum of cue ball = momentum of balls
struck + remaining momentum in cue ball)
What outside force acts
against the balls now?
If a larger truck were to run, head
to head, into a smaller truck
moving at the same speed,
what would happen to the
momentum of each truck?