Answer:
(a) We are asked to compute the Brinell hardness for the given indentation. for HB, where P= 1000 kg, d= 2.3 mm, and D= 10 mm.
Thus, the Brinell hardness is computed as

![=2*1000hg/\pi (10mm)[10mm-√((1000^2-(2.3mm)^2) ]](https://img.qammunity.org/2021/formulas/engineering/college/ns0det8soeds9x6m48uvauqcwe8r9sw61a.png)
(b) This part of the problem calls for us to determine the indentation diameter d which will yield a 270 HB when P= 500 kg.
![d=\sqrt{D^2-[D-(2P)/((HB)\pi D) } ]^2\\=\sqrt{(10mm)^2-[10mm-(2*500)/(450( \pi10mm)) } ]^2](https://img.qammunity.org/2021/formulas/engineering/college/3f2c457bq8yvtxr3vvs4k0qyjvv1mui32y.png)