BRAINCAKEMaterials
Revision notes for Materials in AQA Physics (7407). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- DensityThe density of a solid, liquid or gas is the mass per unit volume of the substance.
- Measuring DensityTo measure the density of an irregular solid measure the mass and then immerse the object in a liquid and measure the volume displaced.
- The Density of AlloysThe density of alloys can be calculated by adding the masses of each individual metal to get the total mass and adding the volumes of each…
- Hooke's LawHooke's Law states that the force needed to stretch a spring is directly proportional to the extension of the spring up to the limit of…
- Springs in ParallelWhen two springs are placed in parallel the effective spring constant is the sum of the two spring constants.
- Springs in SeriesWhen two springs are placed in series the total extension is the sum of the individual extensions of each spring. ΔLP = W kP ΔLQ = W kQ ΔLP + ΔLQ W…
- The Energy Stored in a Stretched SpringThe energy stored in a stretched spring is stored as elastic potential energy.
- Tensile and Compressive ForcesTensile forces and compressive forces cause the deformation of solids.
- Tensile StressTensile stress σ is given by: σ = T/A where T is the load and A is the cross-sectional area.
- Tensile StrainTensile strain ε is the extension over the original length. ε = ΔL/L Where ΔL is the extension and L is the original length.
- Young ModulusThe Young Modulus is a property of a material and is independent of the dimensions of the material.
- Stress-Strain Graph for Metal WireStress-Strain Graph for a metal wire P limit of proportionality E elastic limit Y1 yield point (weakens temporarily) yield point small increases in…
- DefinitionsPlastic Deformation Material no longer returns to original length when force is removed.
- Other Stress-Strain CurvesSteel is ductile and has a high tensile strength.
- Loading and UnloadingLoading and Unloading a Metal Wire The loading and unloading line is the same provided the elastic limit is not exceeded.
- Strain EnergyThe area under the force-extension graph is equal to the work done to stretch the wire.
- PolytheneThe extension during unloading is greater than the extension during loading and the material does not return to its original length.
- RubberThe change in length during unloading is greater than during loading for a given tension.