On May 30, 5:34*am, Mxsmanic wrote:
terry writes:
Its not a bad thing at all, as long as you are sure the other person
is indeed wrong.

Why do I have to be sure? *(Although I typically am.)

well if you are not sure, it would be polite to say so instead of
using your usual authorative tone, but that is an issue of normal
human interaction and ettiquette, I dont expect you would understand
that.

But where you have gone wrong on this group is too
many times you have told people incorrectly that they were wrong, that
will really **** a lot of people off.

Why would I care about that? *People who react in that way are reliably
stupid, and I'm not interested in talking to stupid people.

That pretty much says it all. You want people to help you but you
dont give a **** what they feel or how you treat them.
No wonder you live your life in front of a computer screeen, but I'm
guessing it wont be long before your computer even walks out on you.

And then to make it worse,
there have been people who would still take the time to explain to you
why you were wrong, and you would refuse to accept it or acknowledge
you were wrong.

Examples?

I gave you an example, cacluculating the density of a parcel of
atmosphere from the gas laws. remember?

Come to think of it I cant recall a single time you admitted you
were wrong.

That's because I'm not often wrong, but I admit it when it is the case.

I'd like to see that.

Example? * would you like
to tell us again why we cant apply the ideal gas law to calculate the
air density of a parcel of air we want to fly in.

You cannot use the combined laws (note the nuance) because the volume of the
atmosphere is not constrained.


PV=nRT
substitue n for m/M

gives m/V ( density ) = PM/RT

notice how volume is now removed from the equation?

so for any parcel of air where the pressure and temp are effectively
constant, ie like at an airport that might interest a pilot, you can
calculate density by simply knowing the pressure and temperature, this
can then be related to density height and performance of the
aircraft. Explain why the non constrainment effects that
relationship?

Of course most pilots dont get out the calcuator and do this
calculation, they use tables that do effectively the same thing. But
they use the measured pressure ( the altimeter is effectively a
pressure meter) and read outside temperature from the thermometer, and
then use tables to read off density altitude ( density) which would
give you the same result as if I measured the pressure with a
barometer, temperature with a thermometer and used the ideal gas
equation in the form as given above, to calculate density and then
refer this density to the ISA atmosphere.

I suggest you cross understanding of gas laws off your list of non
trivial knowldege

Terry
PPL Downunder