Question

A steel bar 100 mm (4.0 in.) long and having a square cross section 20 mm (0.8 in.) on an edge is pulled intension with a load of 89,000 N (20,000 lbf), and experiences an elongation of 0.10 mm (4.0 x 10^-3 in.). Assuming that the deformation is entirely elastic, calculate the elastic modulus of the steel.

Answer 1

The elastic modulus of the steel is 139062.5 N/in^2

Step-by-step explanation:

Elastic modulus = stress ÷ strain

Load = 89,000 N

Area of square cross section of the steel bar = (0.8 in)^2 = 0.64 in^2

Stress = load/area = 89,000/0.64 = 139.0625 N/in^2

Length of steel bar = 4 in

Extension = 4×10^-3 in

Strain = extension/length = 4×10^-3/4 = 1×10^-3

Elastic modulus = 139.0625 N/in^2 ÷ 1×10^-3 = 139062.5 N/in^2