Chapter 6 Section 3

Objectives:

Calculate the momentum of moving objects

Explain the law of conservation of momentum

Momentum:

A quantity defined as the product of the mass and velocity of an object

The more momentum an object has the harder it is to stop the object or change its direction

Calculating Momentum:

Momentum (p)

p = m x vo M = mass (kg)o V = velocity (m/s)o Momentum units = (kg • m/s)o Momentum, like velocity, has direction

Math Focus

Text page 167

Momentum calculations…

Now its your turn #1-2

The Law of Conservation of Momentum

Any time objects collide, the total amount of momentum stays the same

True for any collision if no other forces act on the colliding objects

Applies whether the objects stick together or bounce off each other

The Law of Conservation of Momentum

http://www.physast.uga.edu/~rls/1020/ch5/fig5-5.jpg

Objects Sticking Together Sometimes objects stick together after a

collision

They will then move as one object

In a head-on collision the combined objects move in the direction of the object with the initial greater momentum

Mass and velocity change

Objects Sticking Together

http://www.physicsclassroom.com/mmedia/momentum/fca.gif

http://www.physicsclassroom.com/mmedia/momentum/fcb.gif

Objects Bouncing Off Each Other In some collisions, objects will bounce off

each other

Momentum is usually transferred from one object to another

The result is the object move in different directions at different speeds

Total momentum remains the same

Objects Bouncing Off Each Other

http://www.codeproject.com/KB/recipes/GravitySimulation/GravitySimulation3.JPG

Conservation of Momentum & Newton’s 3rd Law

Action – Reaction forces

http://simplethinking.com/teaching/newtonlaws_files/image002.jpg

Quick Quiz:

What is the equation for momentum?

Give an example of an object that has a large momentum. Explain your answer.