Question

What is the increase in length of a bar of length l due to a tensile load p? Assume cross sectional area is a and elastic modulus of the bar is e

Answer 1

we know, elastic modulus is the ratio of stress to strain, stress is the load applied per unit area and strain is change in length of material per unit length.

e.g., elastic modulus = FL/A∆L

where F is load applied on bar.
∆L is increase in length of bar due to applied load, L is original length of bar and A is cross sectional area.

here, L = l, A = a , F = p and elastic modulus = e

so, e = Pl/a∆L

or, ∆L = pl/ae

hence, increase in length of the bar = pl/ae