This is very large spring constant because the wire (taken as a whole) is very stiff. __Note: the units of N/m for k.__
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This is very large spring constant because the wire (taken as a whole) is very stiff. //Note: the units of N/m for k.//
==== Finding the number bonds in the wire ====
==== Finding the number bonds in the wire ====
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The value that we found for the interatomic spring stiffness of Platinum (41.52 N/m) is typical of most pure metals, which have a range from about 5 to about 50 N/m.
The value that we found for the interatomic spring stiffness of Platinum (41.52 N/m) is typical of most pure metals, which have a range from about 5 to about 50 N/m.
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==== Young's Modulus ====
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===== Young's Modulus =====
Like density, the interatomic spring stiffness (ks,interatomic) is an [[http://en.wikipedia.org/wiki/Intensive_and_extensive_properties#Intensive_properties|intensive property]] of an object, it doesn't depend on the length or shape of the object. Other properties are [[http://en.wikipedia.org/wiki/Intensive_and_extensive_properties#Extensive_properties|extensive]] such as mass, volume, and the spring stiffness of the whole wire (ks,wire). Scientists and engineers will often work with intensive properties because they characterize the material and not the object. However, the interatomic spring stiffness is not a property that scientists and engineers often use. When discussing the compression and extension of materials, they often use the bulk modulus or [[https://en.wikipedia.org/wiki/Young%27s_modulus|Young's modulus]].
Like density, the interatomic spring stiffness (ks,interatomic) is an [[http://en.wikipedia.org/wiki/Intensive_and_extensive_properties#Intensive_properties|intensive property]] of an object, it doesn't depend on the length or shape of the object. Other properties are [[http://en.wikipedia.org/wiki/Intensive_and_extensive_properties#Extensive_properties|extensive]] such as mass, volume, and the spring stiffness of the whole wire (ks,wire). Scientists and engineers will often work with intensive properties because they characterize the material and not the object. However, the interatomic spring stiffness is not a property that scientists and engineers often use. When discussing the compression and extension of materials, they often use the bulk modulus or [[https://en.wikipedia.org/wiki/Young%27s_modulus|Young's modulus]].
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=== Stress and strain ===
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==== Stress and strain ====
[{{ 183_notes:mi3e_04-018.png?100|Hanging a mass m on the end of a wire with relaxed length L and cross-sectional area A results in an elongation (stretch) ΔL.}}]
[{{ 183_notes:mi3e_04-018.png?100|Hanging a mass m on the end of a wire with relaxed length L and cross-sectional area A results in an elongation (stretch) ΔL.}}]