Answer to Question #268413 in Electric Circuits for Forida

Question

What do you mean by the Young’s modulus for steel is 𝒀 = 𝟐. 𝟎 × 𝟏𝟎𝟏𝟏 𝑵𝒎−𝟐 ? Explain briefly

Answer 1

If a metal bar of cross-sectional area A is pulled by a force F at each end, the bar stretches from its original length L₀ to a new length L_n. (Simultaneously the cross section decreases.) The stress is the quotient of the tensile force divided by the cross-sectional area, or F/A. The strain or relative deformation is the change in length, L_n − L₀, divided by the original length, or (L_n − L₀)/L₀. (Strain is dimensionless.) Thus Young’s modulus may be expressed mathematically as

Young’s modulus = stress/strain = (FL₀)/A(L_n − L₀).

for steel:

(FL₀)/A(L_n − L₀)=$2.0\cdot10^{11}$ N/m²