Presentation on theme: "Unit 3 Chapter 12 Day 1 OBJECTIVE:"— Presentation transcript:
1 Unit 3 Chapter 12 Day 1 OBJECTIVE: Unit 3 Chapter 12 Day 1 OBJECTIVE: Explain how motion is affected by forces and Describe how gravity and air resistance affect falling objects.Do Now:Project VocabularyToday:Physics Project IntroductionObjects in Free Fall TestForces power point notes and Picture PromptsHomework:Read Chapter 12.1 and 12.1 GRWSPHYSICS FORCE & MOTION PROJECTNew NotebookNew Table of Contents
2 Unit 3 Chapter 12 Day 2 OBJECTIVE: Unit 3 Chapter 12 Day 2 OBJECTIVE: Explain how motion is affected by friction and other forcesDo Now:Complete Project VocabularyToday:DVD Field Trip Air ForcesFriction Lab (Finish in class!)Homework:Read Chapter 12.2 and 12.2 GRWSPHYSICS FORCE & MOTION PROJECT
3 Unit 3 Chapter 12 Day 3 OBJECTIVE: Unit 3 Chapter 12 Day 3 OBJECTIVE: Describe inertia, relate mass and weight, and calculate acceleration using Newton’s 2nd LawDo Now:Motion IQToday:Homework GRWS 12.2 check & reviewNewton’s Three Laws notesWhich Law? worksheetCalculating Acceleration…again.?.!.Newton’s 2nd law practice problemsHomework:Read Chapter 12.3 and 12.3 GRWSPHYSICS FORCE & MOTION PROJECT
4 Homework GRWS 12.3 check & review Momentum Notes & Problems Homework: Unit 3 Chapter 12 Day 4OBJECTIVE: Calculate acceleration and momentum of moving objects. Demonstrate relationship between mass and acceleration.Do Now:3 Laws CrosswordToday:Homework GRWS 12.3 check & reviewMomentum Notes & ProblemsHomework:Study Guide questions and problemsPHYSICS FORCE & MOTION PROJECT
5 Unit 3 Chapter 12 Day 5 OBJECTIVE: Unit 3 Chapter 12 Day 5 OBJECTIVE: Identify and describe the universal forces of gravity, electromagnetic, centripetal and nuclear.Do Now:What if Gravity disappeared?Today:Review Study Guide questions & problemsVideo – MythBuster's Penny DropHomework:STUDY FOR Chapter 12 QUIZ MondayContinue PHYSICS PROJECT
6 Unit 3 Chapter 12 Day 6 Do Now: Do Now Folder – 3 pages OBJECTIVE: Demonstrate concepts and skills of Chapter 12Do Now:Do Now Folder – 3 pagesClear your desks. Get a calculator.Today:Physics Chap 12 QuizNotebook – 20 pagesHomework:Current Events – TBDPHYSICS FORCE & MOTION PROJECT
8 Objects in Free FallWhat factors affect a falling object? Perform the following simple activity to begin learning about the forces that act on falling objects.1. Stand beside your desk. Hold a sheet of notebook paper level at eye level. Release the sheet of paper and watch it fall. Describe the motion of the paper.2. Hold a sheet of notebook paper that has been crumpled into a tight ball at eye level. Release the crumpled paper and watch it fall. Describe the motion of the paper.3. How do the motions of the flat sheet of paper and the crumbled ball of paper compare? What forces do you think are acting on each sheet of paper?
10 It weighs around 1. 8 kg and measures about 42 inches (1 It weighs around 1.8 kg and measures about 42 inches (1.08 m) in total length – the body is about 18 inches (0.46 m) long and the tail is 24 inches (0.62 m) long.
12 Forces of Motion Newton’s Three Laws Chapter 12Forces of Motion Newton’s Three Laws
13 Forces Force - a push or pull The ability to change an object's motion StartingStoppingSpeeding upSlowing downChanging directionMay change an object's shapeForces give energy to an objectAll of the forces acting on an object together are known as net forces
14 Balanced forces are equal forces Unbalanced forces are unequal forces No movement or change in movement occursUnbalanced forces are unequal forcesSome change in movement occursGravity is a force that pulls objects toward each otherFriction is a force that slows down motionForces can be represented with arrows called vectors .Vectors show the direction and magnitude of a force .
15 Forces are measured in newtons ( n ) A newton is equal to 1 kg x 1 m/s2
17 Laws Of MotionSir Isaac Newton’s accomplishments laid the foundations for modern scienceNewton had new ideas about gravity, the diffraction of light, forces.He also had ideas about motion, which he called his three laws of motion.First Law - Law of InertiaSecond Law - Law of AccelerationThird Law - Law of Equal and Opposite Forces
19 First Law - Law of Inertia Inertia is the tendency of an object to not change it's motionIf it is moving, it keeps moving in the same directionIf it is at rest, it stays at restThe more mass an object has, the more inertia it has.This means that the more mass an object has, the harder it is to move, stop, or change the speed or direction of the object.Objects do not change their motion unless a force acts on themAn object will not start or stop moving, change speed or change direction unless a force acts on it
22 Second Law - Law of Acceleration Force = mass X acceleration (F=ma)~or~Acceleration = force/mass (a=F/m)Mass, force and acceleration are relatedAcceleration is produced when a force acts on a mass. The more mass an object has the more force it takes to cause acceleration.Big masses are hard to accelerate.Small masses are easy to accelerate.Objects accelerate more quickly when a greater force is used.Objects move in the direction they are pushed or pulled
23 This is an example of how Newton's Second Law works: Mike's car, which weighs 1,000 kg, is out of gas. Mike is trying to push the car to a gas station, and he makes the car go 0.05 m/s2. Using Newton's Second Law, you can compute how much force Mike is applying to the car.
25 Third Law - Law of Equal and Opposite Forces Forces act in pairsThe forces are equal and oppositeWhen one object exerts a force on another object, the second object exerts a force of equal strength in the opposite direction on the first objectThe first force is the action force.The second force is the reaction force.The equal and opposite forces act on different objects
27 Let's look at how a rocket works to understand Newton's Third Law. The rocket's action is to push down on the ground with the force of its powerful engines, and the reaction is that the ground pushes the rocket upwards with an equal force.
28 Review…1. Who was the scientist who gave us the Laws of Motion? 2. How many Laws of Motion are there? 3. What is another name for the first law of motion? 4. Which law explains why we need to wear seatbelts? 5. Which law says that force is equal to mass times acceleration (F=MA)? 6. Which law says that heavier objects require more force than lighter objects to move or accelerate them? 7. Which law explains how rockets are launched into space? 8. Which law says that for every action there is an equal and opposite reaction?
30 Momentum in the Vernacular In everyday experience, momentum is the amount “oomph” an object hasSo what factors affect the momentum of an object?
31 What affects Momentum? Which has more “oomph”? A biker going at 20 mph A car going at 20 mphA car will certainly hurt more, why?Because it is more massive (more mass)
32 What affects Momentum? Which has more “oomph”? A car going at 10 mph The faster car will have more “oomph”, why?Because faster things are harder to stop
33 Momentum Defined Momentum is the product of mass and velocity This is normally written p = m x vWhat are the units of momentum?p = m x vm: kg v: m/sp: kg • m/s :kilogram meters per second
34 p=mvWhat is the momentum a tortoise that weighs 1kg and moves at .05m/s?p=mv=1x.05= .05kgm/sHow does that compare to a bee that weighs 10 grams and flies at 2 m/s?10g=.01kgp=mv=.01x2= .02kgm/sThe tortoise has more momentum.
35 Chapter 12 Formulas m = F / a a = F / m m = p / v v = p / m p = m * v Law of AccelerationF = m * am = F / aa = F / mMomentump = m * vm = p / vv = p / m