It wouldn't effect it unless your worried about the self weight of the rope or cable. Tension is carried uniformly through the rope the only properties that are important in tension members are the stress properties of the material and the cross-sectional area. If your designing a connection or using w-sections you may also need to incorporate shear lag into your calculations. But typically it turns out to be negligible.
If you were not talking about force or stress length does effect the deformation or stretching of the material. The longer the member the more it can stretch. But again for a 30 ft angle I believe it only has 1/8 inch draw so again it's normally negligible.
If you have access check the AISC manual there is an entire chapter on tension members and how to calculate them.
The shorter the rope/cable, the lesser tension it gets. The longer the rope/cable, the greater tension it gets...REGARDLESS OF THE WEIGHT.
Basically the shorter the rope/cable, the harder it is to snap and the longer the rope/cable, the easier it is to snap...REGARDLESS OF THE WEIGHT.
Consider the weight of the cable. If you hang two things from a support, one weighs 1 lb and one weight 20000 lbs, will this effect the load?
increasing and decreasing one would effect the other . try it out and see for your self
WHat effect will increasing and decreasing the length of a steel cable/rope or whatever have on the tension within the cable/rope?
