1. Chapter 6 Section 3 Inertia & Momentum
Unit 2 Force & Motion
Chapter 6 Section 3
Inertia & Momentum

2. Reminder… mass - the amount of matter in an object
the standard unit is kilogram (kg)
many factors, like mass, affect an object’s motion

3. Which is More Difficult?
Why?

4. Inertia
the greater the mass of an object the more difficult it is to speed up, slow down, or turn
inertia - tendency of an object to resist a change in motion
(more mass = more inertia = harder to change motion)

5. Like increasing mass, increasing speed or velocity makes it harder to move an object…
movement could be starting or STOPPING
momentum - a measure of how difficult it is to stop an object
depends on mass and velocity of the object

6. momentum = mass x velocity
Calculating Momentum
momentum = mass x velocity OR
p = mv
standard unit: kilograms times meters per second
(kg • m/s)
since velocity includes a direction, momentum includes direction too
 mass, velocity, or both =  momentum

7. Conservation of Momentum
law of conservation of momentum - the total momentum of objects that collide is the same before and after the collision
can be used to predict how the motions/speeds of objects will change after a collision
2 collision possibilities…
stick together
bounce off each other