Re: Impedance &c.

[Leigh Palmer <palmer@SFU.CA>]

The GR class looks good. The professor teaching the course is a bright
young fellow I interviewed about seven years ago, when he first applied
to SFU. I asked him then about teaching GR, and I knew that if he did,
I would take it. The text (by Hartley) looks good, too. I skated for
only two hours, but it was glorious! The first time in eleven years,
and in the old days we used to skate on Deer Lake about every other
year. It is supposed to snow tonight and then warm up, so I probably
won't get any more skating in.

On Jan 5, 2004, at 6:11 PM, Chuck Britton wrote:

> My question (suspicion) is:
> are other impedances also going to be expressed as the ratio of an
> intensive variable to an extensive variable - with the product of
> these two variables being power???

Yes, I did indicate that.

> a 'simple' system to analyze would be a spring loaded gun shooting a
> projectile of mass m.

A good example.

> and what IS the impedance of a simple lever system?

A lever has no intrinsic impedance; the quantity impedance pertains to
sources and sinks. A lever (or lever system) is a transformer, ideally
an impedance matching device. It multiplies force by a constant while
dividing velocity by the same quantity. That quantity has the name
"mechanical advantage" at present, but I would like to see a neutral
term adopted.

Leigh