The cable of a uniformly loaded suspension bridge hang in the form of a parabola.
The roadway which is horizontal and 100 m long, is supported by vertical wires attached to the cable, the longest wire being 30 m and the shortest being 6 m. Find the length of a supporting wire attached to a roadway 18 m from the middle.
Equation of ellipse is :
Now,
∴ Equation of ellipse in the standard form is
(i) Focus,
Focus,
(ii) Vertex,
Vertex,
(iii) Length of major axis = 2a = 2(3) = 6
Length of minor axis = 2b = 2(2) = 4
(iv) Let the eccentricity be e.
Now, c = ae,
∴
(v) Length of latus rectum