An engineer determines that a 60 cm long rod of 1045 HR grade of steel will be subjected to a tension of 20kN. The following two designs requirements must be met: must remain below 145MPa and the rod must stretch less than 0.125mm. Determine an appropriate value for the rod's diameter to meet these two requirements. Round to the nearest milimeter

Please give a detailed solution. Show all the steps in a handwritten format. Strictly don't use chatgpt.

A flanged bolt coupling consists of eight d-mm diameter steel bolts on a bolt circle 267 mm in diameter, and four d-mm diameter steel bolts on a concentric bolt circle 190 mm in diameter. If the torque that can be applied is 8166 Nm without exceeding a shearing stress of 43.32 MPa in the bolts, what is the diameter of the bolts? Round off the final answer to two decimal places.

For the stress element below, when a = 9, b = 4, and c = 5, the principal stress σ2 , the smallest normal stress, is:  ____ MPa. Calculate your answer to 1 decimal place. Input then negative '-' sign, if the answer is negative.