A centrifugal pump running at 1200 rpm has a rotor of mass 18 kg mounted overhanging on the shaft. The distance between the bearings is very small compared to the overhanging end and thus the shaft can be considered as a cantilever whose effective length can be taken as 0.5 m. What is the transverse natural frequency? Shaft diameter is 25 mm. What should be the shaft diameter so that the natural frequency is 25 percent higher than the running speed of the pump?