[PHYSICS] How to calculate the extension of a wire. Watch

Borg_Jake
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Hey, I have my physics exam within the week, and my teacher did not really explain the topic of "Extension" that well. I have been doing some physics past papers, and have stumbled upon this question.

A load of 60N is applied yo a steel wire of length 2m and cross-section area of 0.22mm^2. the Young's modulus of steel is 210GPa. What is the extension produced?

Could someone please show me how to carry out this problem?
Thanks a lot
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GotMyIonYou
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Strain is the extension per unit original (unstretched) length. Strain = x/L
Stress is the force per unit cross-sectional area. Stress = F/A
Young's Modulus = Stress/Strain

Quite a common question from when I've been doing some papers. Basically you are working backwards from the Young's Modulus. You can do it two ways.
Substitute both equations for stress and strain into the Young's Modulus equation and rearrange for x if you are happy with algebra
Or doing it in stages you can calculate:
- Stress
- Strain
- Then extension

Be careful with your units , would also be a good idea to make sure you understand the various stress/strain graphs and how they relate to the materials properties (brittle/ductile, ultimate tensile strength, plastic/elastic), also comes up quite often
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