determine the weight of the heaviest traffic lighting system that can be carried by two bars shown if the allowable stress bar AB is 90MPa and the bas AC is 112 MPa given that the cross sectional areas of bar AB is 50mm^2 and that of AC is 75mm^2

Solid mech.

An aluminum rod 20 mm in diameter and 5 m long is subjected to an axial tensile load of 50 kN compute strain if E for rod is 70x103 Mpa. O a. 5.67x10-3 O b. 2.87x10-3 O. 3.27x10-3 O d. 2.27x10-3

In the section shown, a steel diagonal brace has a tension stress on it (from wind load) = 18.12 ksi. Calculate the effect of 55 degree Fahrenheit rise in temperature that affect the diagonal brace (pinned connections). If the total maximum allowed stress due to tension is 21.6 ksi. Is the stress developed due to thermal (in addition to wind) will be safe compared to the max allowed (21.6 ksi)? coef of thermal expansion for steel = 6.5 x 10-6  in/in/F E (modulus of elasticity - steel) = 29,000 ksi Hint for solving: Calculate the total stress from thermal expansion and add it to the tension stress from wind Stress from thermal expansion is given by the equation  fthermal in ksi =  �  x ΔT x E (mod of elasticity)