申論題

3. Consider the work of a force (F) being defined by its movements dr. When dr is an imaginary displacement of a body in static equilibrium, the imposed displacement results in a virtual work.

(b)Figure 3 shows a W(kg) hemisphere supports a cylinder having a specific weight of p kg/m?. If the radi of the cylinder and the hemisphere are both r, please determine the height h of the cylinder which will produce neutral equilibrium in the position shown. (20%)