(19) The peak amplitude of a single-degree-of freedom system under harmonic excitation is found to be 5 cm. If the undamped natural frequency of the system is 10n rad/sec and the amplitude of the harmonic force is five times the spring constant (k) where k is measured in N/cm, find (a) damping ratio, (b) the amplitude of the system at frequency 20n rad/sec.

QI: A portion of an automobile suspension system consists of an elastic spring and a viscous damper, as shown. If the natural frequency is 10 rad/sec, a) Determine the damping ratio so that any oscillations that occur will decay from 11-0.5 m to x2-D 0.025 m. b) If the system is displaced 0.2 m from its equilibrium position, and released from rest, determine the position of the mass after it has ascillated through 3 cycles.

A rotating machine of 400 kg is similar to the system shown below. It operates at 3600 rpm (note: 1 rpm = 2π/60 rad/s). The machine is unbalanced such that its effect is equivalent to a 4 kg mass located 20 cm from the axis of rotation. An isolator with a spring stiffness of 8x106 N/m and a damping constant of 2x104 Ns/m is placed between the machine and the foundation. Determine the steady state response of the system. Find the force transmitted to the foundation and transmissibility of the isolator.  Find the damping ratio of the system  ζ . Find the transmissibility of the system,  Tf. Find the frequency ratio of the system, β.          Find the amplitude of the harmonic excitation force of the system,  Fo in Newton (N). Find the displacement amplitude of the steady state response of the system, X  in millimeters (mm).  Find the damped frequency of the system,  ωd  in rad/s. Find the force transmitted to the foundation,  FT  in Newton (N). Find the frequency of the harmonic…

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