I can calculate only UTS but some questions I don't know how to attempt

[Martin TSK]

Homework Statement

Hello guys. Please help me how to attempt this question.
The maximum load in a tensile test on a mild steel specimen is 90 kN. If the test piece is 12 mm in diameter, calculate
a) the UTS
b) the working stress
c) the greatest allowable load on 25 mm in diameter
d) state Hooke's law
(Take factor of safety as 3)

Relevant Equations

Uts = max Load/Area

 

[hmmm27]

What progress have you made in answering the question, so far ? Show some work.

 

[Martin TSK]

What progress have you made in answering the question, so far ? Show some work.

UTS = Max load/Area
Uts =90000N/0.00045 m²
UTS =200Megga N/m²

 

[mjc123]

If 12 mm is the diameter, what is the area?

 

[Martin TSK]

What progress have you made in answering the question, so far ? Show some work.

 

[berkeman]

@Martin TSK -- Please stop posting your handwritten work with dim sideways pictures. They are unreadable; I have processed your latest image above to make it upright and improve the contrast, but it is still very hard to read and comment on your work.

Instead, please look at the "LaTeX Guide" link at the top of the Edit window. Please post your math work in LaTeX so it is legible and easier for us to quote and comment on. Thank you.