Amaterial is subjected to a horizontal tensile stress of 90 mpa, a vertical tensile stress of 120 mpa and a shear stress of 75 mpa. find: . the principal stresses .the maximum shear stress the shear stress, acting alone that would produce the same the single tensile stress, acting alone that would produce the same principal stresses maximum shear stress

A)-in the process of engineering design, explain the contribution of material selection. b)- explain the procedure of synthesis as is employed in engineering design. c)- is there any relationship between ergonomics and engineering design? explain. d)- safety consideration in engineering design includes human, product and the enviroment . explain how safety will be incorporated into the design?