"force" is defined incorrectly.

[Chris-Cunningham]

Since Force is kg m/s^2, and

mass: 8000
length: 1
time: 20

We should have force: 8000+1-40 = 7961

However, in "kinds", force is incorrectly described with the identifier 7981. So, a N_s will be described as a force if you use Qty('1 N_s').kind()

[Chris-Cunningham]

I'm rather new to github, but I will try to fix and and make a pull request.

[rage-shadowman]

FYI - I just looked into ruby-units and in "lib/ruby_units/unit.rb" (line 105) force is defined as 7961 (as @Chris-Cunningham has stated). In that same file, 7981 is labeled "momentum".

It might be worthwhile to resync the kinds between ruby-units and js-quantities again.

[gentooboontoo]

Closed (PR #18 merged). New issue #19 created to reconcile kind definitions with ruby-units.