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.
The equation of ellipse is :
Now,
∴ Equation of ellipse in standard form is
Focus,
Focus,
Vertex,
Vertex,
Length of major axis = 2a = 2(4) = 8
Length of minor axis = 2b = 2(1) = 2
Let the eccentricity be e.
Now, c = ae
Length of latus rectum =