### Re: num_cmp problem with lb, lbf when answer is in N, kN..

by Alex Jordan -Is the "m" in "mpsi" ever interpreted as "milli"?

At https://github.com/openwebwork/pg/blob/master/lib/Units.pm, you can see how units are defined. "lb" is:

'lb' => {

'factor' => 4.4482216152605,

'm' => 1,

'kg' => 1,

's' => -2

},

So it's 4.4482216152605 m kg / s^2. In fact, if the answer is "1 lb" (aka "1 lbf"), you can enter "4.448 m kg /s^2" and it will be marked correct.