Week 26-Momentum

The Law of Conservation of
Momentum

Finishing up Unit Seven

What is
Conservation?

What is conservation? Can you think of
some examples?

-National Parks

-Coral Reefs

-Highway Clean-up Projects

Conservation is keeping something the
same. So… “conservation of
momentum” means that the total
momentum of two objects is the same
before and after the objects collide.

The Law Says…

​

BUT WAIT!
What’s an isolated system?

…That for a collision occurring between
two objects in an isolated system, the
total momentum of the two objects
before the collision is equal to the total
momentum of the two objects after the
collision.

A Physical System

In physics, there are three types of
system: Open, Closed, and Isolated.

What kind of system you have is
determined by whether or not energy
and matter can enter or leave the
system.

(1)

In Open Systems, energy and matter

can enter or leave the system freely.

(2)

In Closed Systems, energy can enter or

leave the system freely, but matter

cannot enter or leave the system.

(3)

In Isolated Systems, energy and matter

cannot enter or leave the system.

Which means…

..that the law of conservation of
momentum talks about systems where
no energy or matter leaves the system.

If no energy can leave the system, then
the total amount of energy (or
momentum) two objects have before
they crash is the total amount of
energy they’ll have after they crash.

Example

A Newton’s Cradle

Example

Billiard Balls

Example

Bumper Cars