Question

3. A wire of length 2.00 m and radius 1.0 mm is stretched by 25.0 mm on application of a force of 10³ N. Calculate the Young's modulus of the wire.

Accepted Answer

Cross-sectional area A = πr² = π(1×10⁻³)² = 3.142×10⁻⁶ m².
Young's modulus = Tensile stress/Tensile strain = (Force/Area)/(Extension/Length) = (Force × Length)/(Area × Extension) = (1000×2.0)/(3.142×10⁻⁶×2.5×10⁻²) ≈ 2.55×10¹⁰ Nm⁻².

WAEC Physics 2015 Theory — Question 3

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