# need some explaination

hi everyone
" Damping is the measure of a machine 's ability to absorb energy . Thus , a relative UNDAMPED vibration can be high in amplitude and relative narrow band ."

the bold sentence not make me confuse , some body can drop some comment to explain.

Thanks

Original Post

This is better explain with a formula wich i dont remember exactly but ill try my best.

Vibration amplitud is directly proportional to dynamic force, more force more vibration.

Vibration amplitud is inverse proportion to the dynamic resistance (as I remember here comes your damping factor), less damping damping means higher vibration.

VibAmp = Force/Resistance

And narrow band means a small range of frequencies (around a resonant frequency).

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thanks FBURGOS . your comment very clear and directly concerning about my question . have a nice day

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Resistance is a function of stiffness, damping, and mass.  It varies with frequency.

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and 1 more question :Mixing frequency .

When 2 frequencies are present  + 1 cause + effect relationship is absent -> The Hight frequency will be RIDING the LOW frequency .(1)

When there is 1 cause + 2 frequency can mix together the result is amplitude modulation (2)

for the sentence (1) i not understand how this could be ?

and the sentence (2) how can 2 frequency can mix ? are they trule or it is a theory ?