A 45 kg machine is placed at the end of a 1.6 m long cantilever beam of elastic modulus 200 x 109 N/m and cross-sectional moment of inertia 1.6 x 10-5 m4. As it operates, the machine produces a harmonic force of magnitude 125 N. Determine the operating speeds of the machine at which the machine's steady-state amplitude is less than 0.2 mm. Take keq = 3 EI/L3.