Axial loads are applied with rigid bearing plates to the solid cylindrical rods shown in the figure. The diameter of aluminum rod (1) is

2.00 in., the diameter of brass rod (2) is 1.75 in., and the diameter of steel rod (3) is 3.00 in. Determine the axial normal stress in each of

the three rods. Assume P = 8 kips, Q = 4 kips, R = 10 kips and S= 21 kips. The normal stress is positive if tensile and negative if

compressive.