Do Now

Do NowComplete IOD 402 handoutWhen finished, turn over.

Start a new notes page (with header) and copy down the definitions for all BOLD words in Ch. 5.

Air resistanceInverselyNewtons second lawpressureGrade Do NowPass 1 person to your leftUnit 1 Exam Results!There are still a couple of people who need to make up the exam, so I cant hand you back your test quite yet but here are the resultsA1 72% B1 (8+27.3)/45A2 70% B2 (7.5 + 25.9)/45A3 69%B3 (30.1 + 8.5)/45

You all did great! Im so proud of you!! Newtons 2nd & 3rd LawsUnit 2 Day 3Oct. 3/4 , 2012Todays ObjectivesSWBAT explain Newtons 2nd and 3rd laws.SWBAT give examples of Newtons 2nd and 3rd laws.Newtons 2nd LawF = maForce = mass x acceleration

UnitsForce is in Newtons (N)Mass is in kilograms (Kg)Acceleration is in m/s2

PracticeHow much force is needed to accelerate a 1400 kilogram car 2 m/s2?Write your GIVEN and UNKNOWN

Write the EQUATION

SUBSTITUE numbers for the letters in the equation

SOLVE for the unknown

PracticeHow much force is needed to accelerate a 1400 kilogram car 2 m/s2?Write your GIVEN and UNKNOWNa = 2 m/s2 m = 1400 KgWrite the EQUATIONF = m x aSUBSTITUTE the numbers for letters in the equationF = 1400 kg x 2 m/s2 SOLVE for the unknownF = 2800 N

PracticeHow much force is present when a 2000 Kg elephant is falling with an acceleration of 40 m/s2?Write your GIVEN and UNKNOWN

Write the EQUATION

SUBSTITUTE the numbers for letters in the equation

SOLVE for the unknown

PracticeHow much force is present when a 2000 Kg elephant is falling with an acceleration of 40 m/s2?Write your GIVEN and UNKNOWNa = 40 m/s2 m = 200KgWrite the EQUATIONF = m x aSUBSTITUTE the numbers for letters in the equationF = 2000 kg x 40 m/s2 SOLVE for the unknownF = 80000 N

PracticeHow much force is present when a 300 Kg shoe is falling from the sky with an acceleration of 9.8 m/s2?Write your GIVEN and UNKNOWN

Write the EQUATION

SUBSTITUTE the numbers for letters in the equation

SOLVE for the unknown

PracticeHow much mass is needed for a car to have a force of 40 N with an acceleration of 25 m/s2?Write your GIVEN and UNKNOWN

Write the EQUATION

SUBSTITUTE the numbers for letters in the equation

SOLVE for the unknown

PracticeHow much mass is needed for a truck to have a force of 200 N with an acceleration of 10.2 m/s2?Write your GIVEN and UNKNOWN

Write the EQUATION

SUBSTITUTE the numbers for letters in the equation

SOLVE for the unknown

PracticeHow much acceleration is needed for a 7000 kg semi truck to have a force of 400 N?Write your GIVEN and UNKNOWN

Write the EQUATION

SUBSTITUTE the numbers for letters in the equation

SOLVE for the unknown

PracticeComplete # 19 - 21 on page 72 in your book.Newtons 2nd Law proves that different masses accelerate to the earth at the same rate, but with different forces.We know that objects with different masses accelerate to the ground at the same rate.However, because of the 2nd Law we know that they dont hit the ground with the same force.

F = ma98 N = 10 kg x 9.8 m/s/sF = ma9.8 N = 1 kg x 9.8 m/s/s

Newtons 3rd LawFor every action, there is an equal and opposite reactionNewtons 3rd LawAccording to Newton, whenever 2 objects interact with each other, they exert forces upon each other. When you sit in your chair, your body exerts a downward force on the chair and the chair exerts an upward force on your body.

Newtons 3rd Law

Flying gracefully through the air, birds depend on Newtons third law of motion. As the birds push down on the air with their wings, the air pushes their wings up and gives them lift.Consider the flying motion of birds. A bird flies by use of its wings. The wings of a bird push air downwards. In turn, the air reacts by pushing the bird upwards. The size of the force on the air equals the size of the force on the bird; the direction of the force on the air (downwards) is opposite the direction of the force on the bird (upwards).Action-reaction force pairs make it possible for birds to fly.Other examples of Newtons 3rd LawThe baseball forces the bat to the left (an action); the bat forces the ball to the right (the reaction).

Other examples of Newtons 3rd LawConsider the motion of a car on the way to school. A car is equipped with wheels which spin backwards. As the wheels spin backwards, they grip the road and push the road backwards.

Drawing Force DiagramsForce Diagrams are also called, Free Body Diagrams

Practice drawing a diagram of a person sitting in a chair.

Drawing Force DiagramsPractice drawing a diagram of a bird flying in the air.

Drawing Force DiagramsPractice drawing a diagram of a bat hitting a ball.

PracticeFirst Finish putting your Ch. 5 vocabulary in your notes if you havent already.Second work on questions #1 10 on page ____ in your notes.