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Materials - Coggle Diagram
Materials
Hooke's Law
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For a material obeying Hooke's law, the applied force is directly proportional to the extension
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The force constant of a spring is a measurement of the stiffness of the spring. The higher the force constant the larger force required to stretch or compress the string
Force-Extension Graphs
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plastic deformation - the material has been permanently changed, and will not return to its original length when the force is removed
The area under the graph is the work done on the spring, and so the elastic potential energy that has been stored in the spring
Materials Deforming
Metal - Obeys Hooke's law until the elastic limit of the metal. Before the elastic limit the loading and unloading graphs are the same, but after it the unloading graph is parallel to the loading graph but not identical.
Rubber - does not obey Hooke's law. The rubber will return to it's original length when the force is removed, but the loading and unloading graphs are not the same, as more work is done stretching the rubber than is done when it is released.
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Properties of Materials
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Tensile strain - the fractional change in the original length of the material. It is the ratio of the original length and the new length, and so has no unit.
Young Modulus - represents the stiffness of a material. It is the ratio of stress to strain and so has the unit pascals.
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