Q$2)$

Two solid cylindrical rods $AB$ and $BC$ are welded together at $B$ and loaded as shown. Knowing that the average normal stress must not exceed $175$ MPa in rod $AB,$ determine the smallest allowable values of $d_1.$

HINT Please, show your work. Solve the problem before $=\frac{P}{A}$ choosing vour answer. Do not guess

Choose the right answer from the list below:

$15\mathrm{.}3mm,22\mathrm{.}6mm,22\mathrm{.}2mm,17\mathrm{.}3mm$

$(20$ pts$)$