Asteel bar 100 mm long and having a square cross section 20 mm x 20 mm is pulled in
tension with a load of 89,000 n. under this load it experiences an elongation of 0.10 mm.
assuming that the deformation is entirely elastic, calculate the elastic modulus of the steel.

222.5 Gpa

Explanation:

From definition of engineering stress,

where F is applied force and A is original area

Also, engineering strain, where l is original area and is elongation

We also know that Hooke's law states that

Since A=20 mm* 20 mm= 0.02 m*0.02 m

F= 89000 N

l= 100 mm= 0.1 m

By substitution we obtain

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