1. Newton’s First Law of Motion
8th Grade Science
Mrs. Gergel

2. Cup and Penny Activity Place the index card on top of the cup
Place the penny on top of the index card
Gently flick the card forward
What happens to the penny?
Why do you think this happens?

3. Newton’s Own Words…
“A body at rest preserves in its state of rest, or of uniform motion in a right line unless it is compelled to change that state by forces impressed upon it.”
What does this mean in your own words?

4. Newton’s First Law
An object at rest remains at rest, and an object in motion continues in motion at a constant velocity in a straight line, unless acted upon by an external force or unbalanced force.
Newton’s First law is also known as
The Law of Inertia!

5. Example
Think about how difficult it can be when you are ice skating to make the turn at the end of the rink – your body wants to keep going straight and you have to learn just how much force to apply to your skates at just the right angle to move yourself off of that course without flailing wildly or crashing into the wall.
Walter Lewin, For the Love of Physics pg. 39

6. Inertia
Inertia is the tendency of an object to resist a change in motion
The greater the mass, the greater the inertia
The outside force mentioned in Newton’s first law is often friction
Friction is a force that opposes motion

7. Friction and Newton’s First Law
The unbalanced force that causes an object to stop is called friction
Remember, Friction is a force that opposes motion

8. Crash Test Build your ramp as shown on the board.
Place a hot wheel car at the top of a ramp
Let the car go.
Repeat the demonstration but place a penny on top of the car.
Then, answer your conclusion questions.

9. Exit Quiz!!!
You will have until the end of class to complete the exit quiz!
When you are finished, please flip your quiz over and wait quietly until everyone is done!