# I Physics -- Need help understanding the concept of resonance please

1. Dec 17, 2017

### danial3333

I need help about the concept of resonance.
I will be thanksful if someone help me.

Please consider a system has two natural frequencies, and resonance will occure at two these natural frequencies. Now my question is what is different between these two renosances that has occured? And Which property do have those two natural frequencies?

Last edited by a moderator: Dec 17, 2017
2. Dec 17, 2017

### lekh2003

3. Dec 17, 2017

### FactChecker

The response of a system to different frequencies can be handled separately and summed. It's not clear what you mean by "what is different" and "which property". A system can respond to different frequencies in the same axes, on different axes, or on overlapping sets of axes. The same can be said about the states of a system -- two resonant frequencies can affect the same states, different states, or overlapping sets of states. It can be analysed by looking at the eigenstructure of the (linearized) system.

Last edited: Dec 17, 2017
4. Dec 17, 2017

### Mister T

Each is the frequency of a different mode of vibration.

Frequency of vibration is a property of the system. It doesn't make sense to say that frequency has a property.

5. Dec 17, 2017

### FactChecker

A system will have certain properties at any frequency: gain and phase shift. The properties of a frequency are the frequency, wave length, and amplitude.
At a resonant frequency, it is important to know the system gain, which determines if it is stable or divergent. This includes frequency 0, which will either fade exponentially to 0 or grow exponentially to infinity. If the frequency is non-zero, the amplitude of the cycles will still grow or fade exponentially. One property that is nice to know is the "time to double", which tells you how much time there is to control any divergent behavior.

6. Dec 19, 2017

### danial3333

Thanks for Helping