A small engine has been mounted on a structural system. The engine will run at 1800rpm with an unbalanced massof 28.5*10^-3kg at a radius of 0.15m.The structure has a vertial stiffness of 86.7KN/m. A free vibration test has been run to estimate the damping when the engine till for the firt 21st oscillations. The test measured of a frequency of oscillation f 15Hz and a ratio of amplitude f 22.0. What vibration amplitude will the system have with the engine running at full speed?