The following data refer to a shaft held in short bearing:
Diameter of shaft = 1.5cm; length of shaft = 1m; weight of a disc at the centre of the shaft = 15 kgf; eccentricity of the centre of gravity of the disc from the centre of the rotor = 0.03 cm. modulus of elasticity for shaft material = 2$\times$109 kgf/m2.
Find the whirling speed of the shaft in r.p.m.