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 Vocabulary•Today:• Physics Project Introduction• Objects in Free Fall Test • Forces power point notes

and Picture Prompts•Homework:• Read Chapter 12.1 and 12.1 GRWS• PHYSICS FORCE & MOTION PROJECT

New NotebookNew Table of Contents

Unit 3 Chapter 12 Day 2 OBJECTIVE:

Explain how motion is affected by friction and other forces

•Do Now:•Complete Project Vocabulary •Today:•DVD Field Trip Air Forces• Friction Lab (Finish in class!)•Homework:•Read Chapter 12.2 and 12.2 GRWS•PHYSICS FORCE & MOTION PROJECT

Unit 3 Chapter 12 Day 3 OBJECTIVE:

Describe inertia, relate mass and weight, and calculate acceleration using Newton’s 2nd Law•Do Now:

•Motion IQ•Today:•Homework GRWS 12.2 check & review •Newton’s Three Laws notes•Which Law? worksheet

•Calculating Acceleration…again.?.!.•Newton’s 2nd law practice problems

•Homework:•Read Chapter 12.3 and 12.3 GRWS•PHYSICS FORCE & MOTION PROJECT

Unit 3 Chapter 12 Day 4OBJECTIVE:

Calculate acceleration and momentum of moving objects. Demonstrate relationship between mass and acceleration.

•Do Now:•3 Laws Crossword•Today:•Homework GRWS 12.3 check & review •Momentum Notes & Problems•Homework:•Study Guide questions and problems•PHYSICS FORCE & MOTION PROJECT

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 & problems•Video – MythBuster's Penny Drop •Homework:

•STUDY FOR Chapter 12 QUIZ Monday•Continue PHYSICS PROJECT

Unit 3 Chapter 12 Day 6OBJECTIVE:

Demonstrate concepts and skills of Chapter 12

•Do Now:•Do Now Folder – 3 pages•Clear your desks. Get a calculator.•Today:• Physics Chap 12 Quiz•Notebook – 20 pages

•Homework:•Current Events – TBD•PHYSICS FORCE & MOTION PROJECT

• 2nd Law Acceleration Lab

Objects in Free Fall

What 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?

• 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.

FIRST LAW OF CARTOON PHYSICS

Chapter 12Forces of Motion

Newton’s Three Laws

Forces• Force - a push or pull– The ability to change an object's motion• Starting• Stopping• Speeding up• Slowing down• Changing direction

–May change an object's shape– Forces give energy to an object–All of the forces acting on an object

together are known as net forces

–Balanced forces are equal forces• No movement or change in movement occurs

–Unbalanced forces are unequal forces• Some change in movement occurs

–Gravity is a force that pulls objects toward each other– Friction is a force that slows down motion– Forces can be represented with arrows

called vectors .• Vectors show the direction and magnitude of a

force .

• Forces are measured in newtons ( n )

•A newton is equal to 1 kg x 1 m/s2

THREE LAWS BY NEWTON

Laws Of Motion• Sir Isaac Newton’s accomplishments laid

the foundations for modern science–Newton 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 Inertia• Second Law - Law of Acceleration • Third Law - Law of Equal and Opposite Forces

First Law - Law of Inertia

• INERTIA – Inertia is the tendency of an object to not change it's

motion» If it is moving, it keeps moving in the same direction» If it is at rest, it stays at rest

– The 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 them

» An object will not start or stop moving, change speed or change direction unless a force acts on it

Second Law - Law of Acceleration

Force = mass X acceleration (F=ma)~or~

Acceleration = force/mass (a=F/m)

• Mass, force and acceleration are related– Acceleration 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

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.

 

Third Law - Law of Equal and Opposite Forces

• Forces act in pairs• The forces are equal and opposite

•When one object exerts a force on another object, the second object exerts a force of equal strength in the opposite direction on the first object

• The first force is the action force.• The second force is the reaction force.

• The equal and opposite forces act on different objects

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.

Let's look at how a rocket works to understand Newton's Third Law. 

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?

Review…

What is Momentum?

Momentum in the Vernacular

• In everyday experience, momentum is the amount “oomph” an object has

So what factors affect the

momentum of an object?

What affects Momentum?Which has more “oomph”?–A biker going at 20 mph–A car going at 20 mph

A car will certainly hurt more, why?

Because it is more massive (more mass)

What affects Momentum?Which has more “oomph”?–A car going at 10 mph–A car going at 2 mph

The faster car will have more “oomph”, why?

Because faster things are harder to stop

Momentum DefinedMomentum is the product of mass and

velocity

This is normally written p = m x v

What are the units of momentum?p = m x v

m: kg v: m/sp: kg • m/s :kilogram meters per

second

p=mvWhat is the momentum a tortoise that

weighs 1kg and moves at .05m/s?p=mv=1x.05= .05kgm/s

How does that compare to a bee that weighs 10 grams and flies at 2 m/s?

10g=.01kg p=mv=.01x2= .02kgm/s

The tortoise has more momentum.

Chapter 12 FormulasLaw of Acceleration

F = m * a

m = F / a

a = F / m

Momentum

p = m * v

m = p / v

v = p / m