Can someone please explain to me what Performance Factor is?

[benedictes]

Can someone please explain to me what "Performance Factor" is?

I wasn't sure where to post this, but as the title implies I need someone to explain to me what the concept of "performance factor" is. I'm not sure if that's the correct english phrase I'm looking for, but that's how my dictionary translated it. In norwegian it would be "godhetsfaktor" if there's anyone from Scandinavia here...

The phrase come to use in the theory of forced oscillation and resonance. My teacher defined it to be $$Q=m\omega_{0}/b$$ with $$m$$ as the mass, $$\omega_{0}$$ as the natural frequency and $$b$$ as the damping constant. We assume weak damping thus $$\delta=b/2m<<\omega_{0}$$ and the amplitude is max when $$\omega\approx\omega_{0}$$.

He also said $$Q$$ equals the amplitude at resonance and is inversely proportional to the width of the resonance curve.

Does this simply imply that $$Q$$ is a ratio that describe forced oscillation? "Just a number" that tells us if the resonance curve is narrow and tall or wide and low?

If I look at the graphs for these two cases, I can easily, and probably wrongfully, imagine that the tall curve represent a less damped oscillation than the low and wide one. Am I wrong to do this? Since we assumed weak damping in the beginning I mean..

Could someone please clarify a thing or two here for me? Got my mid-semester exam coming up waaay too soon...:s

Thanks a bunch!

--

Benedicte

 

[LowlyPion]

I wasn't sure where to post this, but as the title implies I need someone to explain to me what the concept of "performance factor" is. I'm not sure if that's the correct english phrase I'm looking for, but that's how my dictionary translated it. In norwegian it would be "godhetsfaktor" if there's anyone from Scandinavia here...

The phrase come to use in the theory of forced oscillation and resonance. My teacher defined it to be $$Q=m\omega_{0}/b$$ with $$m$$ as the mass, $$\omega_{0}$$ as the natural frequency and $$b$$ as the damping constant. We assume weak damping thus $$\delta=b/2m<<\omega_{0}$$ and the amplitude is max when $$\omega\approx\omega_{0}$$.

He also said $$Q$$ equals the amplitude at resonance and is inversely proportional to the width of the resonance curve.

Does this simply imply that $$Q$$ is a ratio that describe forced oscillation? "Just a number" that tells us if the resonance curve is narrow and tall or wide and low?

If I look at the graphs for these two cases, I can easily, and probably wrongfully, imagine that the tall curve represent a less damped oscillation than the low and wide one. Am I wrong to do this? Since we assumed weak damping in the beginning I mean..

Could someone please clarify a thing or two here for me? Got my mid-semester exam coming up waaay too soon...:s

Thanks a bunch!

--

Benedicte

Welcome to PF.

Would this be related to Q-Factor?
http://en.wikipedia.org/wiki/Q_factor#Physical_interpretation_of_Q

 

[benedictes]

Would this be related to Q-Factor?
http://en.wikipedia.org/wiki/Q_factor#Physical_interpretation_of_Q

Ahh, Wiki! Why didn't I think of that?! Thanks=)