Question

A rectangular steel bar 14mm x 20mm x 250mm long extend by 0.15mm and subjected to a stress of 270N/mm^2.
1) calculate the tensile force of the rectangular steel bar
2) calculate strain of the steel bar
3) calculate modulus of elasticity of the steel bar

Answer 1

1) To calculate the tensile force of the rectangular steel bar, we can use the formula:

Tensile Force = Stress x Cross-sectional Area

First, we need to calculate the cross-sectional area of the steel bar. The cross-sectional area of a rectangular shape is given by the formula:

Area = Length x Width

Area = 14mm x 20mm = 280mm^2

Now we can calculate the tensile force:

Tensile Force = 270N/mm^2 x 280mm^2
Tensile Force = 75,600 N

Therefore, the tensile force of the rectangular steel bar is 75,600 N.

2) To calculate the strain of the steel bar, we can use the formula:

Strain = Change in Length / Original Length

Given that the steel bar extends by 0.15mm and the original length is 250mm, we can plug in these values:

Strain = 0.15mm / 250mm
Strain = 0.0006

Therefore, the strain of the steel bar is 0.0006.

3) To calculate the modulus of elasticity of the steel bar, we can use the formula:

Modulus of Elasticity = Stress / Strain

Given that the stress is 270N/mm^2 and the strain is 0.0006, we can plug in these values:

Modulus of Elasticity = 270N/mm^2 / 0.0006
Modulus of Elasticity = 450,000 N/mm^2

Therefore, the modulus of elasticity of the steel bar is 450,000 N/mm^2.