Force = mass * acceleration, and downward force=weight. Acceleration due to gravity is 9.8 m/sec^2, and so someone who is 100 kilograms would actually weigh 980 newtons. That would make 1kg=9.8nt Another common misconception is people thinking that pounds (lbs) measures mass. Pounds measures weight!! The actual American measurement for mass is a slug, which is 32 pounds (due to gravity's acceleration being 32 ft/sec^2). Well, theres my little physics for the day.