# Review of Conservation of Momentum

## POTENTIAL ENERGY VS KINETIC ENERGY

Potential Energy is stored energy. Examples include a lawn mower filled with gasoline and a car on top of a hill.

Kinetic Energy is energy being used. Examples include a lawn mower cutting grass and a car going down a hill.

## What is the Conservation of Momentum?!

This principle states that for a collision occurring between object 1 and object 2 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. That is, the momentum lost by object 1 is equal to the momentum gained by object 2.

## Example of Conservation of Momentum

Looking at figure 1A, the momentum is zero because there is no movement, but when they push apart in figure 1B their momentum is equal to mv1 + mv2.

If their masses are equal they both recoil with the same (but opposite) velocity.

## If the two are of unequal mass...

Then the individual with a greater mass will move slower after the initial push as seen in Figures 2A and 2B