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# Resonance/ Damping watch

1. Can someone explain light damping to me

Basically I have 2 books and I think they are saying two separate things but I'm not sure which is the correct one.

So the first one says: Light damped systems have a very sharp resonance peak. Their amplitude only increases dramatically when the driving frequency is close to the natural frequency.

The other one basically has a graph and it shows that light damping reduces the amplitude and the fo (natural frequency? I think) decreases slightly

What confuses me is if there is light damping why would the amplitude (sharpness of the peak) increase? Surely you would want it to be less?
2. (Original post by Super199)
Can someone explain light damping to me

Basically I have 2 books and I think they are saying two separate things but I'm not sure which is the correct one.

So the first one says: Light damped systems have a very sharp resonance peak. Their amplitude only increases dramatically when the driving frequency is close to the natural frequency.

The other one basically has a graph and it shows that light damping reduces the amplitude and the fo (natural frequency? I think) decreases slightly

What confuses me is if there is light damping why would the amplitude (sharpness of the peak) increase? Surely you would want it to be less?
A system that is damped lighter than another will have a higher resonance peak than the other system. This is simply because there is less resistive force against the motion.

You seem to be confusing the curve for resonance with the curve for the motion of the body. It is true that the amplitude of an oscillating body will decay with time under the influence of a damping force - the nature of that decay depends on the type of damping. However, that is not what the book is trying to say. The book is trying to say that if you force a damped system into oscillation then the system with lightest damping will display the highest amplitude under resonance. This makes sense: if you are trying to resonate a swing through air vs resonate it through mud, the swing through air will have the highest amplitude at resonance, because its damping is lighter than the mud.

However, the natural frequency of the body does not change with respect to damping. It is an intrinsic property of that body.

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