So I was going to write a comment about how you actually can adjust weight and mass independently based on W = mg if you can control gravity, and that comment relied on the assumption that kg measures mass and lb measures weight...
Except the latter is not true! In US customary and other systems that use the avoirdupois pound, 1 lbm := 0.45359237 kg exactly. However, there is also a pound-force, which is lbf := (1 lb) × (gravitational acceleration in ft/s^2 ). This gives rise to the slug, yet another unit of mass defined as slug := (1 lbf) ÷ (1 ft/s^2 ) = 32.17404 lbm. I actually used this unit in my differential equations class because my professor was really old-school.
The source of the confusion is that the "pound" as a unit of measurement (really one of several units) predates the distinction between mass and weight.
Moral of the story: if handed US customary units, just convert to metric (SI). And I guess I have to write lbf or lbm now whenever I'm forced to use US customary.
