Monday, March 3Monday, March 3rdrd Entry TaskEntry Task

Write down the following definitions and Write down the following definitions and match them up with the correct termsmatch them up with the correct terms

Definitions:Definitions:

1.1.The rate at which velocity changes The rate at which velocity changes with timewith time

2.2.A measure of mass in motionA measure of mass in motion

3.3.The force that keeps an object moving The force that keeps an object moving in a circlein a circle

Terms: centripetal force, acceleration, Terms: centripetal force, acceleration, mass, contact force, momentummass, contact force, momentum

Schedule:Schedule:• Gravity notesGravity notes

Objective: Objective: •I can understand that I can understand that gravity is a force gravity is a force exerted by masses exerted by masses

HomeworkHomework• 12.1 RSG and 12.1 RSG and

handouts (if not handouts (if not finished in class)finished in class)

Have on your desk:Have on your desk:• Chapter 12 Chapter 12

IntroductionIntroduction• Week 23 Entry TasksWeek 23 Entry Tasks

What we learned beforeWhat we learned before

• Every action force has an equal Every action force has an equal and opposite reaction forceand opposite reaction force

• Newton’s laws are used to Newton’s laws are used to describe the motions of objectsdescribe the motions of objects

• Mass is the amount of matter an Mass is the amount of matter an object contains.object contains.

Gravity is a force exerted by Gravity is a force exerted by masses.masses.

Gravity is a Gravity is a Universal ForceUniversal Force because it acts between any because it acts between any things with things with massmass..

Gravity requires 2 things with Gravity requires 2 things with mass to be present. mass to be present.

Gravity is a force exerted by masses.Gravity is a force exerted by masses.

Greater distance results in smaller force.

Greater Mass results in greater force

Force of Gravity Depends On…Force of Gravity Depends On…

• Mass of the objectsMass of the objects– More mass More mass greater force of gravity greater force of gravity– If mass is doubled, force of gravity If mass is doubled, force of gravity

doublesdoubles

• Distance between the objectsDistance between the objects– More distance More distance less force of gravity less force of gravity– If distance is doubles, force of gravity If distance is doubles, force of gravity

is 1/4is 1/4thth

Earth exerts a Earth exerts a downward downward (action) (action) force on pencilforce on pencil

Pencil exerts an Pencil exerts an upwardupward (reaction) (reaction) force on Earthforce on Earth

Net force not Net force not strong strong enough to enough to move earth move earth (too much (too much inertia), but inertia), but can move the can move the pencilpencil

Free template from www.brainybetty.com

Gravity accelerates objectsGravity accelerates objects

Acceleration due to Acceleration due to Earth’s gravity is Earth’s gravity is

9.8 m/s9.8 m/s2 2 (1 G)(1 G)

W=W=mgmg• If an object is dropped on Earth it If an object is dropped on Earth it

accelerates towards it because of the accelerates towards it because of the gravitational pull.gravitational pull.

• This acceleration is called This acceleration is called gg – gg=9.8 m/s=9.8 m/s²²

• Newton’s 2Newton’s 2ndnd law (from Chapter 11) law (from Chapter 11)– Formula Formula FF==mama– Substitute w for FSubstitute w for F– Substitute Substitute gg for for aa– w=mgw=mg is the formula for calculating the weight is the formula for calculating the weight

of an object (it’s a force!) close to Earth’s of an object (it’s a force!) close to Earth’s surfacesurface

Gravity accelerates objectsGravity accelerates objects

A thrown object will A thrown object will hit the ground at the hit the ground at the

same time as a same time as a dropped object (If all dropped object (If all

other forces are other forces are absent)absent)

Weight and MassWeight and Mass

MASS – The amount of matter MASS – The amount of matter in an object (Does not change in an object (Does not change

based on surroundings)based on surroundings)

WEIGHT – The amount of WEIGHT – The amount of gravitational force acting on gravitational force acting on

an objects (Does change an objects (Does change based on surroundings)based on surroundings)

Weight is a measure of the Weight is a measure of the force of gravityforce of gravity

Because gravitational pull between you Because gravitational pull between you and the moon is weakerand the moon is weaker,, you weigh less you weigh less on the moon. REMEMBER…Weight and on the moon. REMEMBER…Weight and

mass are different thingsmass are different things

Tuesday,Tuesday, March 4March 4thth Entry TaskEntry Task

Gravity is pulling the Gravity is pulling the moon toward the moon toward the center of Earth. center of Earth.

Write a brief paragraph Write a brief paragraph explaining why the explaining why the moon does not crash moon does not crash into Earth.into Earth.

** 12.1 Quiz ** 12.1 Quiz tomorrow!!! **tomorrow!!! **

Schedule:Schedule:• Relating Mass and Relating Mass and

Weight activityWeight activity

Homework:Homework:• Complete the activity if Complete the activity if

not finished in class.not finished in class.

Objective:Objective:•I will measure and graph I will measure and graph the relationship between the relationship between mass and weight.mass and weight.

Please Have on Desk:Please Have on Desk:• 12.1 Handout & RSG 12.1 Handout & RSG

Wednesday, March 5Wednesday, March 5thth Entry TaskEntry Task

Explain how Explain how weight and weight and mass are mass are different.different.

QUIZ QUIZ TOMORROWTOMORROW HomeworkHomework

• 12.2 RSG12.2 RSG

Schedule:Schedule:• 12.1 Quiz12.1 Quiz• Stomp Rocket IntroductionStomp Rocket Introduction• Friction notesFriction notes• Objective: Objective: I can apply physics I can apply physics

concepts to a human-powered concepts to a human-powered rocket.rocket.

Please have on desk:Please have on desk:• Relating Mass and Weight Relating Mass and Weight

activityactivity

Friction NotesFriction Notes

• Take your own notes-any way you want- on Take your own notes-any way you want- on 12.212.2

• Re-read it, write down important information Re-read it, write down important information such as such as – Vocabulary DefinitionsVocabulary Definitions– Labeled DiagramsLabeled Diagrams– Summaries Summaries

• Must have a minimum of one full page in Must have a minimum of one full page in your notebook of thorough notes + the RSGyour notebook of thorough notes + the RSG

• THIS WILL BE GRADED tomorrowTHIS WILL BE GRADED tomorrow

Thursday, March 6Thursday, March 6thth Entry TaskEntry Task

Do you exert a Do you exert a gravitational force? gravitational force? Explain your answer.Explain your answer.

Schedule:Schedule:• Bill Nye, “Friction”Bill Nye, “Friction”• Friction ActivityFriction Activity

Homework:Homework:• Complete activity if Complete activity if

not finished in classnot finished in class

Objective: Objective: •I will describe how I will describe how friction affects motionfriction affects motion

Please have on desk:Please have on desk:• 12.2 Notes and RSG12.2 Notes and RSG

Possible AnswerPossible Answer• Everything that has mass exerts Everything that has mass exerts

a gravitational force. If you a gravitational force. If you have mass…and you do….you have mass…and you do….you exert a gravitational force on exert a gravitational force on those things around you.those things around you.

• Objects are not attracted to you Objects are not attracted to you because there is a stronger because there is a stronger gravitational force very close gravitational force very close by…THE EARTH’sby…THE EARTH’s

Friday, March 7Friday, March 7thth Entry TaskEntry Task

•You want to move a very You want to move a very heavy box from one side of the heavy box from one side of the commons to the other. commons to the other. Explain how you would reduce Explain how you would reduce the friction to make this task the friction to make this task easier.easier.

Schedule:Schedule:• Pressure notes and math Pressure notes and math

practicepractice

Homework:Homework:• 12.3 RSG12.3 RSG

Objective: Objective: • I can describe how I can describe how pressure depends on force pressure depends on force and areaand area

Please have on desk:Please have on desk:• Friction activityFriction activity