ENERGY 1 ENERGY UNITS Energy: The ability to do work (make - - PowerPoint PPT Presentation

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ENERGY 1 ENERGY UNITS Energy: The ability to do work (make - - PowerPoint PPT Presentation

Dec 21, 2023 211 likes •525 views

ENERGY 1 ENERGY UNITS Energy: The ability to do work (make something happen) Joule (J) Calorie (cal) The calories on food packages are really kcal Electron Volt (eV) British Thermal Unit (btu) Kilo watt hours ( kWh )

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SLIDE 1

ENERGY

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SLIDE 2

 Energy: The ability to do work (make something happen)

  • Joule (J)
  • Calorie (cal)
  • The calories on food packages are really kcal
  • Electron Volt (eV)
  • British Thermal Unit (btu)
  • Kilo watt hours (kW·h)

 Your body gets 8,000 J (1,900 cal = 1.9 kcal) of energy from eating a peanut.  6O J of energy are need per second to keep a 60 W appliance running.  1 gallon of gas produces 1.32×108 J of energy or enough energy to keep a 60 W appliance running for 25 days.

ENERGY UNITS

1 cal 4.184 J 1 eV 1.620×10-19 J 1 btu 1055 J 1 kW·h 3.600×106 J

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SLIDE 3

 Work (J)  Work is always a change in energy. How much energy it took to do ____________.

WORK

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 Power (𝑥𝑏𝑢𝑢 𝐾

𝑡 energy per time)

  • Mechanical Power
  • 𝑄 = 𝐺 × 𝑤
  • F = Force (weight 𝐺 = 𝑛𝑕 g = 9.8 𝑛

𝑡2)

  • v = velocity
  • Electrical Power
  • 𝑄 = 𝐽 × 𝑊
  • I = current
  • V = voltage

 The hoover dam on average produces 4.5×104 W per hour.

POWER

Appli liance ance Pow

  • wer

er T.V. 120 W Computer and Monitor 270 W Washing Machine 425 W Refrigerator 725 W Dishwasher 1,800 W Dryer 3,400 W

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Potential  Gravitational  Stored Mechanical  Chemical  Nuclear  Electrical  Sound Kinetic  Motion  Electrical  Radiant  Thermal  Sound

TYPES OF ENERGY

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SLIDE 6

 Energy from position.  𝐹 = 𝑛𝑕ℎ

  • g=9.8

𝑛 𝑡2

  • h=height
  • m=mass

 Examples of gravitational energy:

GRAVITATIONAL

POTENTIAL ENERGY

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SLIDE 7

 Energy from motion.  𝐹 = 1

2𝑛𝑤 2

  • m=mass
  • V=velocity

 Examples of motion energy:

MOTION

KINETIC ENERGY

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SLIDE 8

 Law of conservation of energy

  • Energy cannot be created or destroyed

ENERGY TRANSFER

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 Energy that can be released if a chemical reaction occurs.  Combustion

  • 2C8H18 + 25O2  16CO2 + 18H2O

ΔH=-10,941 𝑙𝐾

𝑛𝑝𝑚

 Examples of chemical energy:

CHEMICAL

POTENTIAL ENERGY

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SLIDE 10

 Energy stored in object by tension.

  • Spring
  • 𝐹 = 1

2𝑙𝑦 2

  • K = spring constant
  • x = distance from at rest position
  • Stretched rubber band

 Examples of stored mechanical energy:

STORED MECHANICAL

POTENTIAL ENERGY

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SLIDE 11

 The energy stored inside the nucleus of an atom.

  • 𝑞𝑛𝑞 + 𝑜𝑛𝑜 ≠ 𝑛𝑜𝑣𝑑𝑚𝑣𝑡
  • 𝐹 = 𝑛𝑑2
  • m = mass
  • c = speed of light 3.00×108 𝑛

𝑡

 Examples of nuclear energy

  • Fission (Breaking atoms apart)
  • 92

235𝑉 + 0 1𝑜 → 56 141𝐶𝑏 + 36 92𝐿𝑠 + 30 1𝑜

  • releases 3.5x10-11 J per reaction (2.1×1013 J per mole)
  • Fission is what happens in nuclear reactors. Although no

pollutant are produced, radio active waste is left over.

  • Fusion (Joining atoms together)
  • 6D  24He + 2p + 2n
  • releases 3×108 kJ per each gram D
  • These are the type of reactions that go on in the sun.
  • In order to get fusion to happen on earth we need to be at high temperatures

(108 K)

NUCLEAR

POTENTIAL ENERGY Fusion Fission

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SLIDE 12

 Potential

  • The energy associated with the attractive force between 2 oppositely

charged particles

  • 𝐹 =

1 4𝜌𝜁°

𝑟1𝑟2 𝑠12

  • ε˚= vacuum permittivity 8.85 × 10−12 𝐷2

𝐾∙𝑛

  • q = charge
  • r = separation

 Kinetic

  • The energy generated from the flow of electrical change (electrons)
  • 𝐹 = 𝑊𝐽𝑢
  • V = voltage
  • I = current
  • t = time

 Examples of electrical energy:

ELECTRICAL

POTENTIAL OR KINETIC ENERGY

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SLIDE 13

 The energy in electromagnetic waves.

  • 𝐹 = ℎ𝜉
  • h plank’s constant 6.626×10-34 J·s
  • Frequency 𝜉 =

𝑑 𝜇

  • c speed of light 3.00×108𝑛

𝑡

  • λ wavelength
  • Examples of radiant energy:

RADIANT

KINETIC ENERGY

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 The energy that is moved through substances with longitudinal waves.

  • 𝐹 = 𝑏2𝜍

2𝜌𝑔 (E in this expression is energy density or energy per area)

  • a = particle acceleration
  • ρ = air density
  • f = frequency of sound

 Examples of sound energy:

SOUND

KINETIC AND POTENTIAL ENERGY

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 Energy that is caused by heat.

  • When thermal energy is applied atoms/molecules move faster.
  • 𝐹 = 𝑔1

2𝑙𝑈

  • f = degrees of freedom
  • k = Boltzmann’s constant 1.381×10-23 𝐾

𝐿

  • T = temperature
  • Examples of thermal energy:

THERMAL

KINETIC ENERGY T=Cold T=Hot

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Potential  Gravitational  Stored Mechanical  Chemical  Nuclear  Electrical  Sound Kinetic  Motion  Electrical  Radiant  Thermal  Sound

TYPES OF ENERGY

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SLIDE 17

WORLD ENERGY

Source ce of Energy gy Perce rcent nt Petroleum 32% Natural Gas 24% Coal 30% Renewable 10% Nuclear 4%

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2014

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SLIDE 18

WORLD ENERGY

Count ntry Energy gy Consumption nsumption (Quadri adrilli lion

  • n Btu)

China na 119.3 Unit ited St States es 98.0 Ru Russia 30.7 India 24.3 Japan an 18.9 Canad ada 14.5 Brazil 12.8 German any 12.7 Korea, South th 11.1 Iran 10.7

Count ntry Energy y Consum nsumpti ption

  • n/p

/person son (MBtu tu)

Qatar tar 1160 United ed Arad Emirat ates es 800 Net ether herlands ands 750 Iceland and 687 Kuwai wait 635 Singap gapore re 633 Bahrai ain 614 Canada ada 427 Norwa way 407 Saudi di Arabia 398 United ed St States es (#14 14) 314

2014

http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm?tid=44&pid=44&aid=2

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SLIDE 19

US ENERGY

Source ce

  • f
  • f

En Energy gy % World ld 2014 14 % US 2014 14 % US 2009 2009 Petroleum 32% 35% 37% Natural Gas 24% 28% 25% Coal 30% 18% 21% Renewable 10% 10% 8% Nuclear 4% 8% 9% US Sources of Energy 2014 (Quadrillion Btu)

http://www.eia.gov/totalenergy/data/monthly/

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SOUTHERN CA EDISON

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http://newsroom.edison.com/stories/sce-increases-its-total-renewable-energy-sources

Source rce of Energy rgy % Edison 2016 % US 2016 Natural Gas 32% 34% Coal 0% 30% Renewable 58% 15% Nuclear 10% 20%

The 2016 Edison numbers recalculate the percentages not using the unspecified sources of power.

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SLIDE 21

UC REGENTS

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COMMUNITY CHOICE AGGREGATION

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2018 2019

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 Voltage (volt V): A measure of its electrical potential .  Which water tower will have water that comes out at a greater pressure?  What represents voltage?

ELECTRICITY

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SLIDE 24

 Current (amps A): The rate of charge flow per time .  Which water tower will have water come out at a faster rate?  What represents current?  Types of Current:

ELECTRICITY

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 Resistance (ohms Ω): The amount of resistance a current will encounter.  Which water tower will have the water encounter more resistance?  What represents resistance?

ELECTRICITY

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 A changing magnetic field induces a electric field.  A changing electric field induces a magnetic field.  Electromagnet: A temporary magnet whose effect is caused by an electric current.

ELECTROMAGNETS

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SLIDE 27

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ELECTROMAGNETS

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 The University of Colorado has computer simulations for different science concepts. Try this one on generators. http://phet.colorado.edu/en/simulation/generator

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 Transformer: An electrical device by which alternating current

  • f one voltage is changed to another voltage.
  • The greater the number of coils the greater the voltage.

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