1. Newton’s First Law of Motion Inertia

2. The tendency of an object to resist any change of motion
Inertia
The tendency of an object to resist any change of motion

3. The amount of matter in an object
Mass
The amount of matter in an object

4. A force that will work against motion in every situation
Friction
A force that will work against motion in every situation

5. Netwon’s First Law- Inertia
Newton develops his famous laws at the age of 24.
1st Law – Every object continues in a state of rest, or of motion in a straight line at constant speed, unless it is compelled to change that state by forces exerted upon it.

6. Inertia

7. For Example Dishes on a tablecloth are in a state of rest.
They tend to remain at rest, even if you snap the tablecloth out from beneath them.

8. Inertia

9. For Example
If you slide a hockey puck along the surface of a city street, the puck will soon come to rest.
If you slide it on the ice, it slides a longer distance. (Due to less friction).
In the absences of forces, a moving object tends to move in a straight line indefinitely!

10. More Examples of Inertia
Blood rushes from your head to your feet when riding on a descending elevator which suddenly stops.
The head of a hammer can be tightened onto the wooden handle by banging the bottom of the handle against a hard surface.
To dislodge ketchup from the bottom of a ketchup bottle, the bottle is often turned upside down, thrust downward at a high speed and then abruptly halted.
Headrests are placed in cars to prevent whiplash injuries during rear-end collisions.
While riding a skateboard (or wagon or bicycle), you fly forward off the board when hitting a curb, a rock or another object which abruptly halts the motion of the skateboard.

11. Mass-A Measure of Inertia
Kick an empty can and it moves. Kick a can filled steel nails and it will not move as much and you will hurt your foot.
The nail filled can has more inertia that the empty can. The amount inertia an object has depends on its mass.
Mass- the amount of material present in an object. If an object has a large mass, it may or may not have a large volume.
The more mass an object has, the greater its inertia and the more force it takes to change its state of motion. Mass is the measure of the inertia of an object.

12. More Mass = Greater Inertia

13. Quiz- Which Has More Inertia?