An electronic scoreboard is to be installed in a large stadium. Due to the design of the roof structure, the suspending cables will have different lengths, as is shown below.
a. Determine a suitable cross-sectional area for each cable so that the scoreboard will hang level, accounting for the stretch in each cable. Use the data in the figure and the requirement that the maximum stress allowed in the cable is 36 ksi. The elastic modulus for the cables is E = 30,000 ksi, and the weight of the scoreboard is W = 10 k. Remember, 1 kip (k) = 1000 pounds.
b. The slope of the grain in the longer support cable has a maximum deviation from the cable's longitudinal axis of 15°, and there is some concern that the relatively low shear strength of the cable material along its grain could cause problems. Calculate both normal and shear stresses along this grain.
