This has errors still (
lbf->N: 0.453592
, 
N->lb: 0.183719
) and I am addressing them...

On Saturday, December 1, 2018, 1:03:41 PM CST, Matt Vinson <matt.vinson@sbcglobal.net> wrote:


Thanks for response....
Yes, yes, yes.  I get that.  I am having trouble understanding the library; not force.  (Same as last time)

I guess I thought the library was magically accounting for gravity which is an error.

Updated:

Thank you,

On Saturday, December 1, 2018, 9:10:38 AM CST, degski <degski@gmail.com> wrote:


On Sat, 1 Dec 2018 at 15:26, Matt Vinson via Boost-users <boost-users@lists.boost.org> wrote:
To see if I understand the library, I want to create metric and imperial systems without using Boost Units predefined systems*.  Conversions between lengths are going well.  Conversion between forces are going well until pounds-force to newtons; line 182 in the link.  What am I doing wrong when lbf will not convert to newtons?


Gravity is not your friend [and gets in the way of what you want to do], you're not doing anything wrong [C++-wise], but you're converting hamburgers to cheeseburgers [for free], they don't convert.

The pound-force is equal to the gravitational force exerted on a mass of one avoirdupois pound on the surface of Earth. Since the 18th century, the unit has been used in low-precision measurements, for which small changes in Earth's gravity (which varies from place to place by up to half a percent) can safely be neglected.[4]

The 20th century, however, brought the need for a more precise definition. A standardized value for acceleration due to gravity was therefore needed.

degski
--
“If something cannot go on forever, it will stop" - Herbert Stein