The armature of a variable-speed electric motor, of mass 200 kg, has an unbalance due to manufacturing errors. The motor is mounted on an isolator having a stiffness of 10 kN/m and a dashpot having a damping ratio of 0.15.
(a) Find the speed range over which the amplitude of the fluctuating force transmitted to the foundation will be larger than the exciting force.
(b) Find the speed range over which the transmitted force amplitude will be less than 10 percent of the exciting force amplitude.