1. Newton’s First Law of Motion: Inertia

2. Newton’s First Law of Motion
“An object remains at rest, or in uniform motion in a straight line, unless compelled to change by an externally imposed force.”

3. In layman’s terms
Objects want to continue doing what they are already doing:
Objects at rest will stay at rest
Objects in motion will continue in that motion (constant speed and direction)
Unless an outside force acts on the object.

4. Still not sure?
Unless there is a force acting on the object, its velocity will not change.
Unless there is a force acting on the object, it will remain at rest

5. Let’s Elaborate No change in speed or direction = CONSTANT VELOCITY
Objects at rest = ZERO VELOCITY
These values remain constant in the absence of a force.
NO FORCE = NO ACCELERATION (because the velocity does not change)

6. And the Scientists?
Aristotle believed that a force was required to keep an object in motion.
Chair Example vs. Projectile Example
Newton and Galileo made the statement that no force is needed to keep an object moving, but will a force prevent it from moving?

7. Frictional Forces Resistive Forces – Opposing motion
Friction and Air Resistance are the two common resistive forces

8. What is Inertia?

9. Let’s talk mass
What is mass?

10. How is inertia related to mass?
We refer to Newton’s First Law as the Law of Inertia
This is the objects resistance to a change in its motion.
So we can define mass as a measure of an object’s inertia, the property that cause it to resist a change in its motion.

11. Inertia and Mass

12. WOULD YOU RATHER?
INERTIA STYLE

13. Try to move: OR

14. Sumo Wrestle OR

15. Try to catch OR