Things to know - Weebly

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Things to know & Concept Symbol Units Kinetic Energy Potential Energy Heat Height Specific Heat Temperature Vocabulary: Energy Kinetic Energy (KE) Potential Energy (PE) Gravitational PE Elastic PE Mechanical Energy Thermal Energy Chemical Energy Electromagnetic Energy Nuclear Energy

Transcript of Things to know - Weebly

Page 1: Things to know - Weebly

Things to know…Concept Symbol Units

Kinetic Energy

Potential Energy

Heat

Height

Specific Heat

Temperature

Vocabulary:Energy Kinetic Energy (KE)Potential Energy (PE) Gravitational PEElastic PE Mechanical EnergyThermal Energy Chemical EnergyElectromagnetic Energy Nuclear Energy

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Energy and Energy TransferEnergy and Energy Transfer

Chapter 15 and 16

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Energy

n Energyn The ability to do workn Work = Transfer of Energy

end

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Energy

n Kinetic Energyn The energy of motion

2

21 mvKE =

end

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Energyn An arrow with a mass of 0.07 kg flies

through the air at 28 m/s. What is the kinetic energy of the arrow?

end

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Practice

• If a 200 kg log rolling down a mountain has 50000 J of kinetic energy, how fast is the log moving?

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Energy

• Complete #1-6 on “Kinetic Energy”

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Energyn Potential Energyn Stored Energyn Many types, but we use Gravitational Potential Energy

mghPE = RememberFg = mg

Fg = weight!

hFmghPE g==end

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Energy

n A rock with a mass of 45 kg is held 2 m above the ground. What is the rock’s potential energy?

end

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Practice

• A man weighing 420kg jumps off a table that is 1.5 m high. What was his potential energy as he jumped off the table?

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Energy

• Complete #1-7 on “Gravitational Potential Energy”

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Energy

nTypes of PEnGravitationalnObject's Height

nChemical nChemical Bonds

n Electricaln Electric charges

n Elastic n Stretching/Compressing

(springs or rubber bands)

n Nuclearn Nucleus of an Atom

end

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Energyn The Law of Conservation of Energy

n Energy cannot be created or destroyedn Can only be converted into another form

50 J 50 J

100 J0 Jend

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EnergyStart:

Ball at rest,

KE = 0

Ball has height, PE = 1000 J

Point 1:

Ball is moving,

KE = 500 J

Ball has lost height,

PE = 500 J

Some PE à KE Point 2:

Ball is moving faster,

KE = 1000 J

Ball has lost ALL height,

PE = 0 J

All PE à KE

Point 3:

Ball is moving slower,

KE = 167 J

Ball has gained height,

PE = 833 J

Some KE à PE

1

end 2

3

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Practice

• A 1000 Kg car is resting at the top of a 43 m hill. How much energy does the car currently have? What kind is it?

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Practice

• An 80 Kg snowboarder is riding a half-pipe that is 15 m deep. If she begins at rest, how fast will she be traveling if there is no friction when she is at the bottom of the pipe?

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Worksheet

• Law of conservation of energy worksheet.

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Section Review

• P. 448 – Math Practice (1-3)

• P.452– Section Review 15.1 (1-5)

• Complete and Turn in with worksheet, done in class!

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Bell Ringer

• What is Kinetic Energy? Formula?

• What is Potential Energy? Formula?

• What does the law of conservation of energy state?

Lab Safety Tip #

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Warm-Up

• What does the law of conservation of energy state?

• A 1200 Kg car is resting at the top of a 65m hill. What kind of energy does it have? Calculate it.

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Ch. 14 Quiz

Turn in When Complete and Finish Roller Coaster Lab

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Bell Ringer

• What are some other types of Energy other than PE and KE?

• What are some ways to increase Energy?

• How does Temperature change as Energy increases or decreases?

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Thermal Energy

n Specific Heat (c)n Heat needed to raise the temp. of a substancen Low Specific Heat = Less Energy Needed

end

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Thermal Energy

n Thermal Expansionn Object heated à it expands (gets bigger)

n In the winter, rings are lose on your fingers

end

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Thermal Energy

n Heatn Transfer of thermal energyn Moves from Hot Objects to Cold Objectsn Measured in joules (J) or calories (cal)

n 1 Calorie (big C from food labels) = 1000 cal

end

TmcQ ∆=Change in Temperature

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Thermal Energyn A piece of iron has a mass of 500 g. If iron

has a specific heat of 0.449 J/g·°C, how much heat must be absorbed to raise the temperature by 95 °C.

end

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Practice

n 100 g of water at 25 °C is placed in a cup. The cup is heated so the water is now at 60 °C. If c = 4.18 J/g·°C, how much heat was absorbed by the water?

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Thermal Energy

• How much heat is given off when 5.0 g of water cool from 75 °C to 25 °C, if the specific heat of water = 4.18 J/g·°C.

• How many joules of heat are necessary to raise the temperature of 25 g of water from 10 °C to 60 °C, if the specific heat of water is 4.18 J/g·°C.

end

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Worksheet

• Complete 1-5 Heat Calculations

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Thermal Energy Transfern3 Ways to Transfer Heat:nConductionn Objects Touchn Touch Hot Stove = Energy into your Hand

n Conductorn Lets heat flown Metal

n Insulatorsn Does not let heat flown Styrofoam

end

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Thermal Energy Transfer

nConvectionnParticles moving aroundnHeat/AC in house/carnOceans, Wind

end

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Thermal Energy Transfer

n Radiationn Infrared (IR) Wavesn All objects radiate heatn Hotter Objects = Give

off Energy Faster

end

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Thermal Energy Transfer

n Thermodynamicsn Study of the transfer of thermal energy n 3 laws

n 1st Law of Thermodynamicsn Energy is conservedn Energy will change forms, but the total

energy is always the same

end

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Energy Transfer

n 2nd Law of Thermodynamicsn Energy can flow from cold to hot objects,

only by doing workn 3rd Law of Thermodynamics

n Absolute zero cannot be reachedn We have reached 0.00000000045 K

end

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Complete Today:Vocabulary: Only These• Heat, Temperature,

Absolute Zero, Calorimeter, Conduction, Thermal Conductor, Thermal Insulator, Convection, Convection Current, Radiation, Waste Heat, Heat Engine

• Complete Worksheet:specific heat

• Section Review: 16.1 & 16.2– P. 478 1-6

• (Read through the section to help find the answers!!!)

– Math Practice• p. 477 1,3,& 5

– 16.2: P.483 1-6