 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

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

 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 )

 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 = 100kg x 5 m/s 2  F = 500 kgm/s (N)  Remember 1 kgm/s 2 is 1 N

 In your table teams, use the equipment in your bins to demonstrate Newton’s Second Law of motion

 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)

 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

1. Doubling the force on a fan cart doubles the acceleration (True/False) 2. 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  3rd

 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?

Action Reaction

 In other words…  Forces always come in matched pairs

ACTION FORCEREACTION FORCE  Any force exerted on one object by another object  From object A to object B  Equal and opposite force exerted by object B to object A 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. It doesn’t matter which of the forces in a pair is called the action force or the reaction force

These two forces are equal and opposite! These forces act between 2 DIFFERENT objects… A pushes on B and B pushes on A

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

 You push down on the ground, and the ground pushes up on you

ROCKET ENGINES EXERT DOWNWARD FORCE ON EXHAUST 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  foreducators/rocketry/home/w hat-is-a-rocket-k4.html foreducators/rocketry/home/w hat-is-a-rocket-k4.html  The rocket pushes on its exhaust  The rocket pushes the exhaust backward

 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"

 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

 ckets/act8.html ckets/act8.html  Rocket interactive NASA  etScience101/RocketScience101.html etScience101/RocketScience101.html

 Balloons  Straws  Paperclips  Tape  String  Ziplock Bags

 Multi Staged Rockets Multi Staged Rockets  ets/act7.html ets/act7.html  9/12/19/balloon-rocket-lab/ 9/12/19/balloon-rocket-lab/  Cornell ask an astronomer  How do rockets work?  hp?number=681 hp?number=681

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

 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.

TRIALTIME (seconds) Balloon Rocket Lab Data Table – Final Round

 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 3rd 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?

 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 Labs/Newt_Laws_Review_Activ.html Labs/Newt_Laws_Review_Activ.html

3/Newton3Intro.html Other Balloon Rocket Lab Resources Teach Engineering.org w.teachengineering.org/collection/cub_/activities/cub_mechanics/ cub_mechanics_lesson04_activity2.xml#objectives Balloon Rocket Worksheet echanics/cub_mechanics_lesson04_activity2_worksheet.pdf