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How much force?
If I suspend a taut steel cable between two poles placed 50 feet apart and suspend a 40 pound weight in the center of the cable, how much force is exerted on each pole by the cable. Assume the cable has no weight, the poles don't bend, and cable is exerting about 75 pounds of force due to it starting tension.
The elastic stretch as a percentage of length is .0402. The diameter of the cable is .125 inches. The length of the cable in inches is 600.
1 Answer
- ?Lv 77 years ago
Depends on the elasticity of the cable, which depends on the size of the cable.
Less elasticity, greater force. More elasticity, less force.
Without that information, the starting tension doesn't matter. If you measured the sag, you could also get it.
EDIT:
"The elastic stretch as a percentage of length is .0402". I'm assuming that stretch is due to the load.
So half of the cable that was previously 25 feet long would after loading become:
l = 1.0402 * 25ft
l = 26.005 ft.
cos(theta) 25ft / 26ft
theta = cos^-1(25/26)
theta = 0.278
Half the weight of the load is borne by each pole.
sin(theta) = 20 pound / T
T = 20 pound/sin(theta)
T = 20 pound / 0.275
T = 72.8 pound
