Introduction to momentum and application of the formula

1. Momentum
updated 2/15/2015

2. ● Increasing either the speed or the mass of an
object makes it harder change that objects
motion [stopping, turning or starting]
● A moving object has a property called
momentum that is related to how much force
is needed to change its motion
● The momentum of an object is the result of:
o MASS and VELOCITY.
● The symbol for momentum is p
● The unit of measurement for momentum is
kg x m/s (kilograms times meters per
second)
Momentum defined & examples

3. Momentum = (mass)(velocity) when you have (#)(#) it means
multiply
p = mv when you have two letters
together it means multiply
As long as you know two out of three parts for the formula you can calculate the
third part
Formulas
EX: If a truck has a mass of 300 kg and a
velocity of 50 m/s then the momentum would
be?
1. write out the formula p=mv
2. identify the numbers you have
momentum: p= ? mass: m= 300 velocity: v =
50
1. plug numbers into formula
p=(300kg) (50m/s)
1. p= 15000
2. add units
p=15000 kg x m/s
Ex: if a truck has momentum of 40 kg m/s and
a mass of 500 kg what would the trucks
velocity be?
1. write out the formula p=mv
2. identify the #s you have
a. p= 40 kg m/s m= 500 kg
v=?
3. plug in the #s
a. 40=(500)v
4. rearrange to solve
a. 40/500=v
5. v=.08 m/s

4. Set up the following problems and solve: show all work AND
remember to include units.
● There is a 500 kg blue van driving along at 50m/s. What is
the blue van’s momentum?
● There is a 350 kg yellow van driving along at 75m/s. What is
the yellow van’s momentum?
● Which van would be harder to stop? Why?
Your Turn: Using the formula

5. ● The momentum of an object does not change
unless it’s:
o mass and/or
o velocity changes
● Momentum can be transferred from one object
to another during collisions
o The results of a collision depend on the
momentum of each object involved
o If a group of objects exert a force only on
each other, their total momentum does not
change
o The amount of momentum lost by the first
object is gained equally by the second
object
Law of conservation of
momentum

6. Read the below scenario and respond to the prompt
Two cars are involved in a head on collision. Car #1 has a mass of 500kg and
a velocity of 30m/s. Car #2 has a mass of 300kg and a velocity of 40m/s.
1. Which car will have the greater momentum?
2. Which car will be forced backward by the momentum of the collision?
3. Based on the law of conservation of momentum if the above two cars
were in a rear ending collision [car #1 running into car #2] explain the role
of momentum and predict the motion path for each car?
Your Turn