Joule Thief 101

[MileHigh]

Brad,

For the record, I will review your last attempt at answering the two wine glass questions in your posting #1696.

How is the resonant frequency of a wine glass determined?

Answer:  "The resonant frequency of a wine glass is determined by the shape,size,and structure of the glass.
We can find out what the resonant frequency is by vibrating the glass using sound waves and raising the frequency of those sound waves until the vibrations of the wine glass reach a maximum amplitude."

>>> You are wrong because you did not identify the two parameters that determine the resonant frequency, the effective mass and the effective stiffness.  The second part of your answer is just silly, describing how to test for the resonant frequency by trial and error.  You are expected to have an innate understanding and the intellectual prowess to know that the question is not looking for that type of "answer."

How does a wine glass resonate, what is the mechanism?

Answer:  "It resonates due to the deformation and reformation  of the wine glass from it's rest shape,where the resonant frequency of this deformation and reformation is determined by the shape,size and structure of the wine glass. This causes pressure wave's that can be heard-->sound waves."

>>> You are wrong because you make no mention of the energy cycling back and forth between kinetic and potential energy where the kinetic energy is in the form of the moving effective mass of the glass and the potential energy is in the form of the glass acting like a compressed spring.  You aren't even close.

MileHigh

[MileHigh]

Webby:

The wine glass _is_ the resonating system.

In physics, resonance describes when a vibrating system or external force drives another system to oscillate with greater amplitude at a specific preferential frequency.

All that quote does is describe a property of a resonating system, that being that it will oscillate at a higher amplitude when stimulated at its natural resonant frequency by an external source.  It's to help you identify a resonant system.

What that quote does not do is describe the mechanism for how the resonance actually works or how the resonant frequency is determined.

MileHigh

https://en.wikipedia.org/wiki/Resonance

[MileHigh]

No, there is no external system, or external force.  It is not within the definition of resonance and it is not a required part of the answer.

You have seen video of skyscrapers oscillating back and forth after an earthquake.  The skyscrapers are resonating.  I think we have seen that a few times from earthquake events in Japan over the past 20 years.

How does a skyscraper resonate, what is the mechanism?
How is the resonant frequency of a skyscraper determined?

Give it a shot.  You don't have to say an earthquake has to happen first, I assure you.

MileHigh

[tinman]

 author=MileHigh link=topic=8341.msg481255#msg481255 date=1461000397]






MileHigh

[/quote]
http://www.netdoctor.co.uk/healthy-eating/a10847/body-weight/
Quote: What determines my weight?
There are a number of factors that contribute towards your weight:
hereditary factors
hormonal abnormalities
lack of exercise
diet
lifestyle.

http://www.thenakedscientists.com/forum/index.php?topic=16494.0
Quote: Iron is a lot heavier than, say, lithium. But what determines its weight? Is it purely the number or nucleons, or does how closely packed the atoms are also have a bearing?

How is the weight of an object determined
Quote wikipedia: Typically, in measuring an object's weight, the object is placed on scales at rest with respect to the earth.
https://www.ups.com/content/us/en/resources/ship/packaging/dim_weight.html
Use a scale to determine the weight of the package.

Are you trying to tell us you can't understand these two sentences, "How is the resonant frequency of a wine glass determined?" and "The resonant frequency of a wine glass is determined by two factors."  You have comprehension difficulties with the meaning of those two sentences?

No,it is !what! determines the resonant frequency--not !how! is the resonant frequency determined.

However, your issues with the English language are well known and well documented and all that you do above is confirm the issues once again.

Reading the last few pages,it would seem that you think many people have trouble with the English language,but it looks like it is you MH that has the problem here.

You were just as vulgar towards me in your own way

Another lie.

From this point on use the dot convention and draw up a schematic and you will be doing something useful.

From this point on,i will do what i like,and if you dont like it--to bad


Brad

[tinman]

Webby:



All that quote does is describe a property of a resonating system, that being that it will oscillate at a higher amplitude when stimulated at its natural resonant frequency by an external source.  It's to help you identify a resonant system.



MileHigh

https://en.wikipedia.org/wiki/Resonance

The wine glass _is_ the resonating system.

The wine glass is 1/2 of the resonating system.
Without the other half of the system,there is no resonance.

What that quote does not do is describe the mechanism for how the resonance actually works or how the resonant frequency is determined.

I have corrected the above sentence so as it is correct.
What that quote does not do is describe the mechanism for how the resonance actually works or what determines the resonant frequency.

Brad