Welcome to Physics Forces

Warm Up Look at your reading on Forces Turn to Page 44 Answer these statements Give an example of a contact force. Give an example of an action-at-a-distance force. 7 minutes WHEN DONE: Record scores and Get out planner

Agenda: summarize in planner Newton’s Second Law Introduction to Egg Drop Project

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

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

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?

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.

F m a F m a — = = The Second Law: Equation Form Directly proportional inversely proportional

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

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

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.

Group Preference Please quietly fill out the sheet to let me know who you think you can work best with this might not be your bestie you want to be successful, who will help you stay on task and do that?

Egg Drop Challenge

Egg Drop Challenge Introduction Read The Situation Your Mission Introduction: The Engineering Design Cycle Answer the questions on Page 3 15 Minutes If you finish early: read next section of packet (“Checkpoint 1”)

Checkpoint 1 Checkpoint 5 Checkpoint 2 Checkpoint 4 Checkpoint 3

Define and Research the Problem Car Safety Features Define and Research the Problem DO: READ questions on Pages 5, 6 and 7 Go to crockphysics.weebly.com Navigate to “Forces” page Day 4 Watch Videos. Pause, rewind and repeat if necessary. ANSWER Questions on Pages 5, 6 and 7 30 minutes Checkpoint 1

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