A rotating machine has a mass of 6 kg and a natural frequency of 5 Hz. Due to a rotating unbalanced mass, the machine is subjected to a harmonic disturbance force meω2sin(ωt). When the machine operates at a frequency of 3.5 Hz, the amplitude of the disturbance force

is 40 N.

a. Design a vibration absorber assuming that the maximum allowable displacement of the absorber is 5 cm.

b. Using MATLABR, write an m-file to plot X1/me versus ω. Use the decibel units to show the vertical axis.