Question

200 kg weight hanged at a free edge of vertical wire of length 600.5 cm when removed the weight, length reduced by 0.5 cm also area of cross-section and also area of cross section is it gets original status then what is the young modulus of wire ? 

(A) 2.35 × 10¹² N/m² 

(B) 1.35 × 10¹⁰ N/m² 

(C) 13.5 × 10¹¹ N/m² 

(D) 23.5 × 10⁹ N/m²

Answer 1

Correct option: (A) 2.35 × 10¹² N/m²

Explanation:

Y = [{stress} / {strain}]

= [{stress} / {(0.5) / (600.5)}]

= [(6005) / 5] × stress             (1)

Also stress = (F/A) = (mg / A)

Given

m = 200 kg

A = 1 mm² = 10^–6 m² 

∴ stress = {(200 × 10) / 10^–6} = 2 × 10⁹ N/m² 

From (1) Y = 1201 × 2 × 10⁹ N/m² = 2.4 × 10¹² N/m²