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26 Cards in this Set
- Front
- Back
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8 energy stores |
-thermal -chemical -kinetic -magnetic -electrostatic -gpe -elastic potential -nuclear |
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4 energy transfers |
-mechanically (work done) -electrically (charges) -heating -radiation (waves) |
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Kinetic energy def |
Energy to this store when object speeds up Energy away from this store when object slows down |
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Kinetic energy depends on? |
Mass and speed |
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Kinetic energy formula |
Ek = 1/2 m v2 |
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Gpe def |
Higher object lifted, more energy transferred to this store |
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Gpe depends on? |
Mass of object, height, strength of gravitational field |
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Gpe equation |
Ep = m g h |
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Link between gpe and ke |
Energy lost from gpe store = energy gained in ke store |
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Specific heat capacity def |
Amount of energy needed to raise temp of 1kg of substance by 1 degree C |
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Power equations |
E/t W/t |
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Lubrication |
Reduces frictional forces Liquids like oil |
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Conduction |
Object heated > energy to ke store of particles > vibrate more, collide > energy transferred between ke stores during collisions |
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Thermal conductivity? |
Measure of how quickly energy is transferred by conduction Higher = faster rate |
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Convection? |
When particles free to move > particles moving faster means space increases > density decreases > warmer less dense region rises > energetic particles move from hotter to cooler regions |
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Insulation |
Reduces rate of energy transfer by heating |
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Efficiency equations |
Useful output energy transfer / total input energy transfer Useful power output / total power input |
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Non renewable resources |
FOSSIL FUELS Coal oil gas NUCLEAR FUELS Plutonium uranium |
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Renewable energy resources |
-sun -wind -water waves -hydro-electricity -bio-fuels -tides -geothermal |
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Wind power |
Turbines with generators that produce electricity No pollution - but spoil view and noisy Unreliable Initial costs high, but minimal running costs No permanent damage |
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Solar cells |
Generate electric currents directly from sun Used in remote places No pollution Cannot increase output when extra demand Initial costs high - but minimal after Small scale energy |
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Geothermal power |
Volcanic areas Slow decay of various radioactive elements Free energy, reliable, little damage Expensive, not many suitable locations |
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Hydro electric power |
Requires flooding of valley by building a dam - water allowed out through turbines No pollution Big Impact on environment Can provide immediate response to increased demand Initial costs high but minimal running costs Small scale electricity |
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Wave power |
Turbines connected to generator Unreliable, spoilt view No pollution Initial costs high but minimal running costs |
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Tidal barrages |
Big dams across estuaries with turbines in them Tides produced by gravitational pull of sun and moon No pollution Reliable, height however variable Minimal running costs, initial costs moderately high |
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Bio-fuels |
Made from plants and waste Reliable, but cannot respond to immediate energy demands (so stored) cost is high Loss of habitats in forests |
