1. Newton's First Law
Concept Summary
Batesville High School Physics

2. Newton’s First Law
Whatever an object is doing, that’s what it wants to keep doing.
If left to themselves, objects will keep doing whatever they’re doing.

3. Newton’s First Law Objects at rest tend to stay at rest.
Objects in motion tend to stay in motion.

4. Newton’s First Law
If there is no net force on an object, the object won’t accelerate.

5. Newton’s First Law The converse is also true:
If an object is not accelerating, then there is no net force on it.

6. What is an “object”?
Anything made of matter is an “object”.

7. What is a “force”?
A force is an interaction between 2 objects involving a push or a pull.
Forces are vectors - they have a direction in space.
Common units of force are: pounds, Newtons, or dynes.

8. What is a “net force”?
The net force on an object is the vector sum of all of the forces that push or pull on the object.

9. “no net force on an object” means:
either there are no forces on the object, or:
the forces that push or pull on the object all cancel exactly.

10. “object won’t accelerate” means:
the object:
won’t speed up.
won’t slow down.
won’t change direction.

11. Newton’s First Law can be stated:
If no forces push or pull on an object, or if the forces that do push or pull on it all cancel exactly, then the object will not speed up, slow down, or change direction.

12. Inertia
Newton’s First Law says that objects do not accelerate spontaneously.
This property of matter, which causes objects to resist acceleration, has been named “inertia”.
Newton’s First Law is often called the Law of Inertia.

13. The End