why do bodies at rest weight more than zero??? here is the bull thing... now im sitting on my chair and i know earth exerts a force on me which is called my weight. by definition w=mg I DO NOT have any acceleration g or anything else. let me prove a = dv/dt my speed is zero v = 0, coz im sitting so a = dv/dt = 0 w = ma = m times 0 = zero which means i have to weight zero. but earth attracts me so it cant be zero. this looks like a contradiction...can anyone tell me why i weight?