31. A dynamic load is one which changes with time fairly quickly in comparison to the structure's natural frequency . 32. :A harmonic is a vibrational mode at a frequency which is an integer multiple of the natural frequency . 33. The values of the spring and mass give a natural frequency of 7 Hz for this specific system. 34. Why are natural frequency formats helpful? 35. Ideally, the natural frequency should be high and the damping factor should be near 0.707 ( critical damping ). 36. Since the system is a 2 DOF system, there are two modes with their respective natural frequencies and shapes. 37. The lowest one in frequency is the fundamental frequency, and the next highest natural frequency is the first overtone. 38. He identified that the failures were caused by one of the blades'natural frequencies being in the engine running range. 39. It wasn't intentional, he says, but the rowers seemed to force the boat to vibrate close to its natural frequency . 40. The total response of the circuit is the resonant frequencies of the ZIR are called the " natural frequencies ".
