Newton’s 1st Law of Motion

Objective: To understand what Newton’s 1st law is and why Newton’s Laws are Important

Who is this Newton Guy?

• Sir Isaac Newton was an English scholar.

• He is most popular for his observations of the world around him.

• Specifically, his 3 laws of motion and gravity.

Ok, So what is a Law?

• What is a scientific law?

• A law is an observation of the physical world that is consistent with how things work.

• A law has not yet been disproved.

Ok, So What is Motion?

• Can you define motion?

• Motion results when an object is in a state of change.

• Examples: moving, stopping, turning, accelerating, etc…

One More Question, Why do I care about these Laws?

• Newton’s laws describe/explain how the universe works.

• Once you see them they will seem simple and logical, but it is important to understand the limitations that have been put on motion.

• These laws are less about what can be done in the universe than they are what CANNOT be done.• These laws tell us what is and is not

possible in the world of motion around us.

What is Newton’s First Law of Motion?

• Newton's first law states that:

• An object at rest will remain at rest and an object in motion will remain in motion unless acted upon by an outside force.

• Pair up with the person next to you and come up with a definition of Newton’s 1st Law in your own words.

Newton’s First Law Continued

• Can you think of a situation in which Newton’s 1st law is not true.

• Don’t feel bad, since they were first published in 1687, no one else has yet been able to disprove Newton’s Laws either.

What are these Forces you speak of?

• A force is anything that changes the motion of an object

• More specifically, it is a push or pull on an object.

• What are the most common forces?• Gravity• Friction• Weight• Air Resistance• Normal • Physical Interactions

Drawing Force Diagrams

• Force diagrams help us to see what is going on with an object at a specific time.

• Always start Forces in the center of the object

• Draws arrows that represent the direction and size of the force

• If there are not arrows/forces that are balanced, then the object is in motion

Newton’s 1st Law Concluded

• Simply stated: Objects do not start or stop moving on their own

• Forces are responsible for all motion in the world

Practice

• In your notes, draw a force diagram for a golf ball sitting on a tee.

• Now, draw a force diagram for a golf ball that has just been hit and is flying through the air.