By breathing in deeply, you can change volume of your body. Suppose a swimmer underwater weighs wf = 23.4 N with his lungs full, and we = 48.0 N with lungs empty. Find change in body volume when swimmer inhales. I know the apparent weight = weight in air - buoyant force and buoyant force = weight of displaced fluid = desnity of liquid x g x volume but how do I solve for the change in volume without weight in air??