GCSE›Edexcel GCSE Physics›Mind mapsWork, Power & EfficiencyEdexcel GCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsWork doneEnergy transferred when a force moves somethingWork done (J) = energy transferred (J)No movement in force direction → no workE=F×dE = F \times dE=F×d20 N pushes a box 3 m → 60 JChanging energyWork done by forcesElectrical equipmentHeatingClosed system: total energy unchangedΔGPE=mgΔh\Delta GPE = mg\Delta hΔGPE=mgΔhKE=12mv2KE = \frac{1}{2}mv^2KE=21mv2Wasted energyEnergy is dissipated into surroundingsEnds up in the thermal storeFriction causes heating and wasteEnergy is conserved, just less usefulWork & powerand efficiencyJWNmPowerPower = rate of energy transferP=EtP = \frac{E}{t}P=tE1 watt = 1 J/s300 J in 5 s → 60 WEfficiencyUseful energy ÷ total energy suppliedDecimal (0–1) or percentageNo device is 100% efficientExam tipsName the route: forces, electrical or heatingShow the equation, substitution and unit