Ndanji678
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A 4kg mass on a wire of original 1.5m. If the wire is extended by 3mm, determine:

1.Tensile strength on the wire if the wire has a diameter of 1mm.
2.Tensile strain.
3.Young modulus.
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alevelphysicist
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1. I think you mean tensile stress, which is equal to force divided by cross-sectional area
The force is the weight of the mass, W = mg
Cross-sectional area, A = pi x r^2

2. Strain equals the extension divided by original length

3. Youngs modulus equals tensile stress divided by tensile strain
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Ndanji678
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(Original post by alevelphysicist)
1. I think you mean tensile stress, which is equal to force divided by cross-sectional area
The force is the weight of the mass, W = mg
Cross-sectional area, A = pi x r^2

2. Strain equals the extension divided by original length

3. Youngs modulus equals tensile stress divided by tensile strain
Thanks a lot.
Though I want to find out why you think (1) should be tensile stress and not strength?
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alevelphysicist
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(Original post by Ndanji678)
Thanks a lot.
Though I want to find out why you think (1) should be tensile stress and not strength?
Glad to help

Because tensile strength is something different which can’t be calculated with the given values and you need to know tensile stress to calculate the Young’s modulus.
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Ndanji678
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(Original post by alevelphysicist)
1. I think you mean tensile stress, which is equal to force divided by cross-sectional area
The force is the weight of the mass, W = mg
Cross-sectional area, A = pi x r^2

2. Strain equals the extension divided by original length

3. Youngs modulus equals tensile stress divided by tensile strain
Thanks a lot.
Though I want to find out why you think (1) should be tensile stress and not strength?
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Adridk
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Tensile strength is related to material properties. Tensile strength is related to the geometry of the part.
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Ndanji678
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(Original post by alevelphysicist)
1. I think you mean tensile stress, which is equal to force divided by cross-sectional area
The force is the weight of the mass, W = mg
Cross-sectional area, A = pi x r^2

2. Strain equals the extension divided by original length

3. Youngs modulus equals tensile stress divided by tensile strain
Thanks a lot.
Though I want to know why you think it should be tensile stress and not tensile strength?
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Ndanji678
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(Original post by alevelphysicist)
Glad to help

Because tensile strength is something different which can’t be calculated with the given values and you need to know tensile stress to calculate the Young’s modulus.
But since you said the force is W=mg can’t we use that to find young modulus?
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Andrew97
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I’ll be honest. I read the title as something different there.
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alevelphysicist
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(Original post by Ndanji678)
But since you said the force is W=mg can’t we use that to find young modulus?
Yes, but finding the tensile stress is the step in between.
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Ndanji678
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(Original post by alevelphysicist)
Yes, but finding the tensile stress is the step in between.
I understand,so can we try to solve this using tensile strength? And see how it’ll go?
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alevelphysicist
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(Original post by Ndanji678)
I understand,so can we try to solve this using tensile strength? And see how it’ll go?
The point I’m trying to make is you can’t find the tensile strength
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Eimmanuel
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(Original post by Ndanji678)
I understand,so can we try to solve this using tensile strength? And see how it’ll go?
Tensile strength and tensile stress are different.
Tensile strength is maximum stress that a material can withstand while being stretched or pulled before breaking.
Tensile stress is the ratio of load to area.
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