GCSE›Edexcel GCSE Physics›Mind mapsForces & ElasticityEdexcel GCSE Physics: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsDistortionElastic: returns to original shapeInelastic: permanently deformedForces can stretch, compress or bendHooke's lawF=keF = keF=keExtension proportional to forceWorks for stretching and compressionExtension = final − natural lengthSpring constantMeasured in N/mLarge k means a stiff springSmall k means a soft springk = gradient of force–extension lineElasticitysprings and forcesFkeLimitsStraight line until limit of proportionalityThen graph curvesPast elastic limit: permanent deformationEnergy storedEe=12ke2E_e = \frac{1}{2}ke^2Ee=21ke2k=40k = 40k=40 N/m, e=0.2e = 0.2e=0.2 m → 0.8 JPast the limit, work done exceeds energy storedExam tipsMeasure natural length firstArea under graph is work done