Hi folks!

Today, I will be taking on the third of the four sample review problems that I have solved last Saturday. For the first problem refer to [1<sup>st</sup>](https://steemit.com/steemiteducation/@josephace135/random-review-problems-in-strength-of-materials) and for the second problem refer to the [2<sup>nd</sup>](https://steemit.com/steemiteducation/@josephace135/random-review-problems-in-strength-of-materials-or-part-2-of-4-5d2563400ef16). Without much ado, let me introduce the third review problem.

``Determine the outside diameter of a hollow steel tube that will carry a tensile load of 500 kilo Newton (kN) at a stress of 140 megapascal (MPa). Assume the wall thickness to be one-tenth of the outside diameter.``
Choices:
 <center></center> | <center></center>   |  <center></center> |  <center></center>
--- | --- | --- | ---
A.	675.2 mm | B. 112.4 mm | C. 78.5 mm | D. 98.4 mm
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Solution:

This review problem is somewhat similar to the 2<sup>nd</sup> problem, the difference is that this problem is looking for the outside diameter (D<sub>o</sub>) of the hollow steel tube and the thickness (t) of the hollow steel tube  is expressed as a fraction of the outside diameter (D<sub>o</sub>). So the computation goes like this:
<center>![image](https://ipfs.busy.org/ipfs/QmQoTpoABYhqdkuajMiTxwae4AjTVg8dbLxJtnXyxG6wnj)
</center>
wherein:
- `σ` is the stress, which can be expressed in terms of pound force per square inch (psi) or in kiloPascal (kPa).
- `F` is the applied, which can be expressed in terms of pound force (lb<sub>f</sub>) or in Newtons (N).
- `A` is the cross sectional area, which can be expressed in terms of square inches (in<sup>2</sup>) or in square meters (m<sup>2</sup>) or in square millimeters (mm<sup>2</sup>).

Interestingly, the problem states that the thickness, `t` of the hollow steel tube is expressed as function of the outside diameter (D<sub>o</sub>), thus we have an equation for the inside diameter (D<sub>i</sub>).
<center>![image](https://ipfs.busy.org/ipfs/Qmb1YGedADHCX54Jjo7FCyWMZ6SRadLBTiybZqy4CWNqVD)
</center>
And finally, we will be able to compute for the outside diameter of the hollow steel tube, by substituting all the data we have and the computations are shown below.
<center>![image](https://ipfs.busy.org/ipfs/Qmd5qbJN1ebgsiWN15SLQ5BnNfF5d7KNC4YrmMaizJQ4ct)
</center>
<center><sub>Thus, we have computed that the outside diameter (D<sub>o</sub>) is equal to ``112.4 mm``; that would satisfy the given parameters such as stress and tensile load. The answer is also found in the choices, which is in letter `B`.</sub></center>
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I guess that would be all for the third review problem relating to **Strength of Materials**, it's pretty easy and I hope you learn from this presentation.

<br>

Thank you for the readers that spent their precious time reading this blog.

<br>

Much love and respect.

<br>

Ace | @josephace135
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<sub>
Presentation of the calculations where made possible using the Equation features of MS Word. All screenshots are made by me and is made possible by Snipping Tool application.</sub>