Young’s Modulus & Elastic Potential Energy — A/L Physics

How do I practise Young’s Modulus & Elastic Potential Energy?

1 question with a worked solution

1. What is the elastic strain energy stored per unit volume (u) in a stretched elastic wire in terms of its Young's modulus Y and tensile strain ε?
   1. A) u = ½ Y² ε
   2. B) u = Y ε²
   3. C) u = 2 Y ε
   4. D) u = ½ Y ε²
   Check my answer

   Correct answer: D) u = ½ Y ε²

   Energy stored per unit volume is u = ½ × stress × strain. Since stress σ = Y × strain ε, substituting gives u = ½ × (Y ε) × ε = ½ Y ε².

   Show worked solution

   Step 1: Energy density u = ½ · stress · strain. Step 2: Stress = Y · ε => u = ½ · (Y·ε) · ε = ½ Y ε². Answer: u = ½ Y ε².
   Modelled on: the A/L Physics examination pattern

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Next in the syllabus

Where does Young’s Modulus & Elastic Potential Energy fit in the syllabus?

Unit 10.2 · Year 2 · Term 3