Name:___________________________________________ Date ______________ Block _______
Notes: Momentum
Part A: Watch the video at: http://www.youtube.com/watch?v=hWToJxKYRSc
1. Describe what happened in this video:
2. Even if a train conductor sees a car on the tracks ahead of time, will she be able to
stop the train in time to prevent a collision? Why do you think this?
Part B: Momentum
Main Idea
Details

The train in the video had ______________________

In order to have momentum, an object must
be __________________________

The car in the video had ___________ momentum.

An object that is _____________________ has
Momentum
zero momentum.

Momentum is a _________________(vector/scalar) which means that
__________________ is important.
Main Idea
Momentum
depends on
two factors
Details

Momentum depends on _____________ and
______________________.

1. mass
An object which has more mass has ( more or less ) momentum than
a less massive object moving at the same speed.


Momentum is ______________________ proportional to mass.
An object which is moving faster has ( more or less ) momentum
than if it were moving slowly.
2. velocity

Momentum is ______________________ proportional to velocity.

Could a toy dump truck ever have momentum than a real dump truck?
Comparing
momentum
Part C: Problem Solving With Momentum
Use your MCAS Forumla sheet to fill in the table:
Symbol for Momentum
(Yes, it’s a _____! You can always look it
up on the MCAS Formula Sheet if you
forget.) 
Formula for Momentum
momentum = mass  velocity
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Sample Problem:
Knowns
How much momentum does a 1400-kg car
moving at 10 m/s have?
Formula & Work
p=?
p = m· v
m = 1400 kg
p = 1400 · 10
Answer
p = 14,000 kg ·m/s
v = 10 m/s
Problem 1:
Knowns
Formula & Work
Problem 2:
Knowns
Answer
A 75 kg skier has a momentum of 750 kgm/s.
What is the skier’s velocity?
Formula & Work
Problem 3:
Knowns
How much momentum does a 2 kg ball moving
at 5 m/s have?
Answer
A dog running at 4 m/s has a momentum of 32
kgm/s. What is the dog’s mass?
Formula & Work
Answer
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Part D: Exploring Collisions & Explosion with Simulations
Open the link http://tinyurl.com/collision-carts
Play with the collisions by changing the masses and the velocities of the carts.
Choose one of each: ELASTIC COLLISION, INELASTIC COLLISION, EXPLOSION.
Fill in the templates with the initial and final conditions
ELASTIC COLLISION (collide and bounce)
Initial (before collision)
Final (after collision)
m1
v1
p 1 = m1 v 1
m1
v1
p1 = m1v1
m2
v2
p 2 = m2 v 2
m2
v2
p2 = m2v2
Total p
pT = p 1 + p 2
Total p
pT = p 1 + p 2
INELASTIC COLLISION (collide and stick)
Initial (before collision)
m1
v1
p 1 = m1 v 1
m2
v2
p 2 = m2 v 2
Total p
Final (after collision)
m
pT = p 1 + p 2
v
Total p
p=mv
p
EXPLOSION (push apart)
Initial (before collision)
m
v
Total p
p = mv
p
Final (after collision)
m1
v1
p1 = m1v1
m2
v2
p2 = m2v2
Total p
pT = p 1 + p 2
What do you notice about the total momentum (p) in every trial (before and after)?
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Part D: Conservation of momentum
Main Idea
Details

When an object with momentum collides with another object,
momentum is transferred.

The Law of
Conservation
of
Momentum 
The momentum that one object loses is ____________ by a
second object
In any collision or explosion, the total momentum remains the
__________.

Momentum cannot be created or destroyed. The amount we
have is constant.
Main Idea
Details

Elastic Collisions: the objects collide and bounce (energy is also
conserved)
o During a game of pool, a moving ball transfers momentum to a
stationary ball. The stationary ball can be caused to start
moving while the moving ball can caused to become
stationary.
Examples
during
collisions
o In baseball, when the bat hits the ball, the bat’s momentum is
transferred to the ball.

Inelastic Collisions: the objects collide and stick (energy is not
conserved)
o Two trains collide, join together, and move on as one
o Two cars crash and their bumpers lock
o A softball catcher catches a ball in her mitt
o A football player tackles another player
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
When an two objects push away from each other (ex: ice skaters
facing each other and pushing apart)

An object breaks apart into pieces (like a bomb)

Momentum is _____________________ in an explosion!

If the object is at rest before the explosion, the momentum of the
object before the explosion is ________________ and the total (net)
Examples
during
explosions
momentum of the pieces after the explosion will be
___________________.

In a system of objects, the momentums of the pieces can cancel when
the objects are moving in opposite directions.
Part E: Changing momentum
Main Idea
Details

Although you could change an object’s momentum by changing either
_________________ or __________________, most situations we
Changing
momentum 
will deal with involve only changing _________________.
To change an object’s velocity, you would need to apply a
__________________.

Therefore, _______________ change the momentum of an object.
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
To stop an object safely, you want it to stop ________________
(quickly/slowly).

When something is stopped slowly,
Stopping
safely



the force is ___________________ (larger/smaller).

the stopping time is ___________________ (larger/smaller).
Examples:

you bend your knees when landing from a jump

air bags
If an object is stopped __________________ (quickly/slowly), there
will be more damage.

When something is stopped quickly,
Stopping
with more
damage


the force is ___________________ (larger/smaller).

the stopping time is ___________________ (larger/smaller).
Example:
 An egg is more likely to break if it lands on a concrete floor
than a pillow
Main Idea
Details

When the train hit the car:
o the car was initially at rest, so its momentum was
____________________
o the train was moving and had a lot of mass, so it had a
Back to the
train…
_________________ momentum
o When the train hit the car, the car started moving

The car _______________ momentum

The train ___________________ momentum

What must have happened to the train’s speed?
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