On the case that the weight of plant is the function of the height of plant, the author considers of the linear oscillatory behaviour of it in turbulent wind. As power spectral density of response at the point of A is represented by the equation (2.1), the problem to solve is identical to get frequency response function of plant. We get f.r.f. as equation (2.14), (2.15) or (2.16), corresponding on end conditions, from the knowledge of mechanics of materials.
Tracing the process above, the answer is available.
