DISTANCE TIME GRAPHS



Energy Transfer - NotesEnergyDefinition: Energy is required to do anything (work) (e.g. heat up).Energy is always conserved, it is never used up or destroyed it is transferred into another form (e.g. chemical to heat).A transducer changes energy from one form to another (e.g. a match).Units: J (joules)Symbol: EEnergy TypesStoreExamplechemicale.g. fuel + oxygen, a batterykineticin a moving objectgravitationaldue to the position of an object in a gravitational fieldelasticin a stretched or compressed springthermal in a warm objectmagneticin two separated magnets that are attracting, or repellingelectrostaticin two separated electric charges that are attracting, or repellingnuclearFrom the nucleus released through radioactive decay, fission or fusionEnergy Transfer Mechanisms (Carriers)TransferExamplemechanicallywhen a force moves through a distanceelectricallywhen a charge moves through a potential differenceheating because of a temperature differenceradiatione.g. light, microwaves, soundEnergy Transfers Phone SpeakersChemical Energy →(electrically transferred) → Kinetic EnergyMatch: Chemical Energy → (thermally transferred) → Thermal EnergyWaste EnergyEnergy is normally wasted as heatWasted energy dissipates (spreads out) into the surroundings.This dissipated energy is too spread out to do useful work and so cannot be re-used.Sankey DiagramFlow diagram drawn to scale showing energy transfers in a machineThe height of the arrows show the amount of energySo the total input height equals the output height17545057366000EfficiencyDefinition: The amount of energy transferred usefully.Can never exceed 1 or 100%.Equation: Efficiency = Useful Energy Output / Total Energy Output Energy output - what energy type is given outEnergy Input – what energy type goes inUseful Energy – output energy that is the intended type and placeWasted Energy – output energy that is either the wrong type or in the wrong place ................
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