Q of D Memorize me 1 kgms 2

Q of D - Memorize me 1 kgm/s 2 = ? � kg measures _______ � N measures ____ � F = ma is ______ � Definitions of 4 fundamental forces � Examples of types of forces � Balanced and unbalanced forces: freebody and vector � How to add and subtract force vectors to determine net force � Newton’s three laws of motion � Examples of Newton’s 3 laws of motion � Inertia– definition and explanations of demos �

OPENER �State Newton’s Three Laws of Motion. �(try without using your notes, then take out your mind map and check your work)

Newton’s Second Law of Motion �F = ma �Force = mass x acceleration �F = Force in newtons (N) �m = Mass in grams (g) �a = Acceleration - how much faster something goes each second - in (m/s 2)

F = ma Practice Problem �An object with a mass of 100 kg accelerates 5 m/s 2 when a force is exerted on it. What is the force? �F = ma �F = 100 kg x 5 m/s 2 �F = 500 kgm/s (N) �Remember 1 kgm/s 2 is 1 N

Take 3 minutes: �In your table teams, use the equipment in your bins to demonstrate Newton’s Second Law of motion

TEST THESE � CHANGE MASS: If you add mass, but keep acceleration the same, force is _______. � CHANGE ACCELERATION: If the acceleration is greater, the force is ______ � CHANGE FORCE: The greater the force, the greater the ______ (given the same mass)

With your team � 1) check your fan cart physics packet � 2) circle a part of the lab that is and example of the First, Second and Third Laws of Motion �COMPLETE THE EXIT SLIP

Fan Cart Exit slip 1. 2. Doubling the force on a fan cart doubles the acceleration (True/False) Doubling the mass of an object halves the acceleration (True/False) 3. Newton’s Third Law is F=ma (True/False) 4. For each action force there is an unequal and opposite reaction force. (True/False) 5. Friction acts in the same direction as the motion of an object (True/False) 6. � � � How does a fan cart demonstrate each of the Laws of Motion? 1 st 2 nd 3 rd

OPENER � How does a fan cart illustrate Newton’s First Law of Motion? � How does a fan cart illustrate Newton’s second law? � TODAY’S OBJECTIVES � Explain and give examples of Newton’s Third Law of Motion � How does a fan cart illustrate Newton’s Third Law of Motion?

Newton’s Third Law Action Reaction

For each action there is an equal and opposite reaction �In other words… �Forces always come in matched pairs

Is it an action force or a reaction force? How can I tell? ACTION FORCE � � Any force exerted on one object by another object From object A to object B REACTION FORCE � Equal and opposite force exerted by object B to object A It doesn’t matter which of the forces in a pair is called the action force or the reaction force The two forces in an action-reaction force pair always act on two different objects. Consequently, the two forces can never cancel each other out. If there are no other forces acting on the objects (such as friction) the objects will accelerate.

When you push on a ball, the ball pushes back on you These two forces are equal and opposite! These forces act between 2 DIFFERENT objects… A pushes on B and B pushes on A

When a bug hits your windshield… Your car exerts a force on the bug, and the bug exerts an equal and opposite force on your car. A is? B is?

When you stand on the ground… �You push down on the ground, and the ground pushes up on you

When a rocket launches… ROCKET ENGINES EXERT DOWNWARD FORCE ON EXHAUST � � The rocket pushes on its exhaust The rocket pushes the exhaust backward ROCKET EXPERIENCES UPWARD FORCE FROM EXHAUST � The exhaust pushes the rocket, too � The exhaust makes the rocket move forward � Upward force is equal and opposite to downward force exerted by engines � You don’t need air to make a rocket work � http: //www. nasa. gov/audience/for educators/rocketry/home/what-isa-rocket-k 4. html

BALLOON ROCKET CHALLENGE �Purpose: �To design and build a balloon-powered "rocket" vehicle to travel across a string with a horizontal engine, an engine at 45 degrees, 90 degrees, then across and BACK. based on Robinson, Conceptual Physics Laboratory Manual, Addison-Wesley, Activity 13, "Balloon Rockets"

THE CHALLLENGE: Rules: You may use only the equipment listed below. No parts (except air) may be added to your vehicle once it begins its trial nor may you blow on your balloon car � You must be able to attach your vehicle to the string without removing the string from its supports. � You may not push (or pull) your vehicle at any time. � The total length of your vehicle must be less than 1 meter. � Your vehicle must start each trial not touching the string. The trip is completed when the vehicle: • is attached to the string touching the first support, then • touches the opposite support, then • touches the starting support for the second time � � �

MATERIALS: �Balloons �Straws �Paperclips �Tape �String �Ziplock Bags

Tips � Multi Staged Rockets � http: //quest. nasa. gov/space/teachers/rockets/ act 7. html � http: //teachingphysics. wordpress. com/2009/1 2/19/balloon-rocket-lab/ � Cornell ask an astronomer � How do rockets work? � http: //curious. astro. cornell. edu/question. php? number=681

The Challenge �The "racecourse" for this activity is a string tightly stretched between 2 supports. (Practice and testing strings may be provided. )

PROCEDURE: �Draw a clearly-labeled sketch of each of your balloon rocket designs. You must get approval before testing each design. �If you change your design as you build and test your rocket, tell why you felt the change was needed and describe (or sketch) the change.

DATA: Balloon Rocket Lab Data Table – Final Round TRIAL TIME (seconds)

REFLECTION � Draw diagrams showing the forces exerted by the balloon and the forces exerted on the balloon. Be sure to make it clear what exerts each force, and what the force is exerted on. (Be particularly clear about which "air" you are talking about. . . ) Which of these forces actually pushes the rocket? What is the Newton's 3 rd Law "partner" of this force? Why don't these 2 forces cancel? If you had an opportunity to redesign your balloon rocket, what would you change, and why?

Newton’s Laws Writing Activity � � Pick a picture in a magazine. Describe how each of the following apply to something in the picture: • Newton's First Law • Newton's Second Law • Newton's Third Law � In your descriptions, be sure that you use each of the following words correctly: • • • force net force mass acceleration velocity http: //www. batesville. k 12. in. us/physics/phynet/mechanics/Newton 3/Labs/ Newt_Laws_Review_Activ. html

Cited Resources on Newton’s Third Law http: //www. batesville. k 12. in. us/physics/phynet/mechanics/Newton 3/Ne wton 3 Intro. html Other Balloon Rocket Lab Resources http: //www. yesmag. ca/projects/balloon_rockets. html Teach Engineering. org http: //www. teachengineering. org/view_activity. php? url=http: //www. teac hengineering. org/collection/cub_/activities/cub_mechanics/cub_mecha nics_lesson 04_activity 2. xml#objectives Balloon Rocket Worksheet http: //www. teachengineering. org/collection/cub_/activities/cub_mecha nics/cub_mechanics_lesson 04_activity 2_worksheet. pdf