b) Bar OA is connect to the ceiling at point C by a spring with the spring constant k. The bar OA could rotate about point 0 as shown in Figure 4. The mass of the bar OA is m with uniformly distributed density, the length of OC and OA are 0.251 and 1, resepctively. Assume that the bar OA is balanced in the horizontal position. Determine the frequency of the vibration of the bar. F k m Figure 4