So I did my test in pencil, and the supervising lady only told me later on as she walked past me. She didn't give instruction on us using pen's so yeah...
What's the procedure if I have used pencil? Will they still mark it? or..? :/
Shear Stress= Force/Cross-Sectional Area
therefore: 150x10^3/50x5 (its 50 because the length of the punch is 25, and thats half the length the plate)
=600MPa
then: 600MPa/2 (divided by two because the punch is half the plate as above ^ in brackets)
=300MPa
:)