
Tom W. answered 08/25/21
MS from Virginia Tech in Engineering Mechanics, 6 yrs TA Experience
The resonance frequency here can also be called the "damped natural frequency." The natural frequency, fn = 32 rad/s, is the natural frequency of the system when it is free from damping. The relationship between undamped and damped natural frequency is as follows:
ωd = ωn ( 1-ς2 )1/2
So: ωd = (32 rad/s) ( 1-0.482 )1/2
ωd = 28.073 rad/s