Wow!

In SI: force is in Newtons
mass is in kg
distance is in meters
time is in seconds - and answers are always in SI units if
you use SI units.

A mass in a gravitational field has a force associated. That force is
not a mass even if it is (some of the time) proportional to mass.

When certain kinds of engineers provide me with specifications
involving pounds I shudder. Each use is converted into its equivalent
in SI. The context helps. An assumption of the strength of the
gravitational field needs to be used. Then I evaluate their work using
SI (and the same assumption about the gravitational field). In SI,
force and mass are quite distinct.
I continue to be amazed by the awesome ability of some engineers to
use a single term for two entirely different things. Use SI and the
answers are SI.
73 Mac N8TT

--
J. Mc Laughlin - Michigan USA
Home:

"J. McLaughlin" wrote:
When certain kinds of engineers provide me with specifications
involving pounds I shudder. Each use is converted into its equivalent
in SI. The context helps. An assumption of the strength of the
gravitational field needs to be used. Then I evaluate their work using
SI (and the same assumption about the gravitational field). In SI,
force and mass are quite distinct.
I continue to be amazed by the awesome ability of some engineers to
use a single term for two entirely different things. Use SI and the
answers are SI.

This captures the essence of the issue. The question is not so much
'are pounds mass or force?', but, rather, 'what did the author
mean when writing pounds?'

An engineer who believes that pounds are always mass will make
just as many errors as one who believes pounds are always force.

....Keith

wrote:
An engineer who believes that pounds are always mass will make
just as many errors as one who believes pounds are always force.

...Keith

Yep. And an engineer who uses pounds for either will either make or
cause more mistakes than one who doesn't. Remember the Mars Climate
Orbiter?

73, Jim AC6XG

On Thu, 25 Sep 2003 23:28:25 -0400, "J. McLaughlin"
wrote:

Wow!

In SI: force is in Newtons
mass is in kg
distance is in meters
time is in seconds - and answers are always in SI units if
you use SI units.

A mass in a gravitational field has a force associated. That force is
not a mass even if it is (some of the time) proportional to mass.

When certain kinds of engineers provide me with specifications
involving pounds I shudder. Each use is converted into its equivalent
in SI. The context helps. An assumption of the strength of the
gravitational field needs to be used. Then I evaluate their work using
SI (and the same assumption about the gravitational field). In SI,
force and mass are quite distinct.
I continue to be amazed by the awesome ability of some engineers to
use a single term for two entirely different things.

It helps to be too stupid to know that there are in fact two entirely
different things. There are several of those people in this thread.

Not for the accuracy of the result, of course. But you can blithely
plug in the numbers and get an answer of some sort.

Gene Nygaard
http://ourworld.compuserve.com/homepages/Gene_Nygaard/