1. Welcome to Physics
Forces

2. Warm Up Turn to Page 44 in your notebook
Read the “momentum” one-page reading
On page 44 write a definition for the physics definition of momentum, based on the reading.
Tape the reading into your notebook on page 46
12 minutes
WHEN DONE: Get out planner

3. Agenda: summarize in planner
Unit 3 Vocabulary Post Pasco Car Activity Newton’s Second Law

4. Learning Targets
I can describe what a force is and where forces come from I can describe how balanced and unbalanced forces affect the motion of an object

5. Writing and Reading Discussion Group Work Instruction Quiet Focused
Active listening
On Topic
Ask Questions
Group Work
Focus on topic
Fulfill Roles
Lean in
Instruction
Listen
Take notes
Raise hands

6. Turn to your Equations and Vocabulary Page
Force
a push or pull on an object in a specific direction. Forces are the result of interactions between objects.
Momentum
a measurement of the amount of motion an object has; the product of an object’s mass and velocity

7. Post Reading Questions
Discuss and revise answers to assigned questions You will be presenting your answers to the class Use your forces reading and your notes to help you answer the questions 10 minutes

8. Share out PASCO Cars Activity

9. Newton’s Laws of Motion
1st Law: a moving object will keep moving and an object at rest will stay at rest unless it experiences an unbalanced force 2nd Law: the acceleration of an object depends on force and mass 3rd Law: for every action, there is an equal and opposite reaction. Or, forces come in pairs.

10. Forces Reading
On page 45 Fold your reading in half Tape into your notebook.

11. Cornell Notes: The 2nd Law
Turn to page 47
Topic:
Newton’s Second Law
Essential Question:
What does Newton’s Second Law say about the relationship between force, mass and acceleration?

12. Learning Targets
I can design, build and evaluate a device that will protect a dropped egg

13. Throwing Eggs

14. The Second Law
The acceleration of an object is directly proportional to the force on the object, and inversely proportional to its mass
In short:
Force goes up, acceleration goes up
Mass goes up, acceleration goes down
We need a model we can use that will help us think about how we can do something about the force experience by an egg as it hit the ground.

15. The Second Law: Equation Form= F m a = —

16. “Its not the fall that kills you. It’s the sudden stop at the end.”
-Douglas Adams

17. F m a — Δv Δt a = = SCENARIO 1: Mass= 1 kg Δv= 4 m/s Δt= 2 s
Make the change in velocity smaller: acceleration experience by the object goes down, and the force experienced by the egg goes down
Make the change in time larger: acceleration experienced by the object goes down, and the force experience by the egg goes down.
SCENARIO 4:
Mass= 1 kg
Δv= 10 m/s
Δt= 2 s
SCENARIO 2:
Mass= 1 kg
Δv= 8 m/s
Δt= 2 s

18. How to protect your egg
Increase the time it take for the velocity to change to zero
Decrease the pre-impact velocity
Create a force that accelerates your egg in the opposite direction
#1: This will reduce the acceleration, and thus the force
#2: This will also reduce the acceleration, and thus the force
#3: This will lower the overall, or net, force experience by the egg. It will accelerate the egg in the OPPOSITE direction.

19. Δv F m = — Δt
Change in Momentum
Impulse

20. When egg hits, the momentum change is constantF
When egg hits, the momentum change is constant t t = F

21. Clean Up
Lab supplies put away Table supplies returned to box Name tags turned in Work turned in Notebooks in backpack Scrapes recycled Stay in your seat until the bell rings