• # question_answer The natural frequency of an undamped vibrating system is 100 rad/s. A damper with a damping factor of 0.8 is introduced into the system. The frequency of vibration of the damped system, in rad/s, is: A) 60                                B) 75C) 80                                D) 100

${{\omega }_{d}}={{\omega }_{n}}\sqrt{1-{{\zeta }^{2}}}=100\sqrt{1-{{(0.8)}^{2}}}$$=\text{ }60\text{ }rad/s$