1. Newton’s 1st Law of Motion
Honors physics

2. Law of inertia
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

3. Inertia

5. What is inertia
Inertia: the resistance an object has to a change in its state of motion.
Prior to Newton's day was that it was the natural tendency of objects to come to rest….. this is wrong!
Objects want to keep doing what they are already doing.
Mass is a measure of an objects inertia (mass = inertia)!

6. what is a balanced force?

7. what is a balanced force?
Forces all cancel out.
The net (total) force is equal to zero.
The item is said to be in a state of equilibrium.
This means there is no acceleration.

8. what is an unbalanced force?

9. what is an unbalanced force?
Forces don’t cancel out.
The net force is NOT equal to zero.
There will be an acceleration.