Answer and Explanation:
Data provided in the question
Force = 50N
Length = 5mm
diameter = 2.0m =
![2* 10^(-3)](https://img.qammunity.org/2021/formulas/physics/high-school/fvlc6oqrg4d1ibrqa3k9l8k2gsi51pen1p.png)
Extended by = 0.25mm =
![0.25* 10^(-3)](https://img.qammunity.org/2021/formulas/physics/high-school/sk6bl6x1xmyg79m7jmre63l4996sbdz8w6.png)
Based on the above information, the calculation is as follows
a. The Stress of the wire is
![= (force\ applied)/(area\ of \ circle)](https://img.qammunity.org/2021/formulas/physics/high-school/t7off6nss7eqqmcl7j9pqmifj2qyay5cz6.png)
here area of circle = perpendicular to the are i.e cross-sectional i.e
=
![(\pi d^(2))/(4)](https://img.qammunity.org/2021/formulas/physics/high-school/qt25si00iei9dj1qphb108ojlxo1u0u08g.png)
=
![(\pi(2* 10^(-3))^2)/(4)](https://img.qammunity.org/2021/formulas/physics/high-school/hwr3hq28wyrf8nku64tcq66npu5is48hvb.png)
Now place these above values to the above formula
![= (4* 50)/(\pi* 4 * 10^(-6)) \\\\ = (50)/(\pi)](https://img.qammunity.org/2021/formulas/physics/high-school/yz1nhwguz6z9ik0y2syva8rjfuuzrsvly2.png)
= 15.92 MPa
As 1Pa = 1 by N m^2
So,
MPa = 10^6 N m^2
b. Now the strain of the wire is
![= (Change\ in\ length)/(initial\ length) \\\\ = (0.25* 10^(-3))/(5)](https://img.qammunity.org/2021/formulas/physics/high-school/79q4l1b0cwcb1s8tbj8j4lwg0t2rqmc8lt.png)
=
![5 * 10^(-5)](https://img.qammunity.org/2021/formulas/physics/high-school/v5nm230jqjnh9f7v3cpysfnlkv5rn2v3ol.png)