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.

From Wikipedia (https://en.wikipedia.org/wiki/Pound_(force)):

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

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